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Nozumi M, Sato Y, Nishiyama-Usuda M, Igarashi M. Identification of z-axis filopodia in growth cones using super-resolution microscopy. J Neurochem 2024. [PMID: 38946488 DOI: 10.1111/jnc.16162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 05/02/2024] [Accepted: 06/10/2024] [Indexed: 07/02/2024]
Abstract
A growth cone is a highly motile tip of an extending axon that is crucial for neural network formation. Three-dimensional-structured illumination microscopy, a type of super-resolution light microscopy with a resolution that overcomes the optical diffraction limitation (ca. 200 nm) of conventional light microscopy, is well suited for studying the molecular dynamics of intracellular events. Using this technique, we discovered a novel type of filopodia distributed along the z-axis ("z-filopodia") within the growth cone. Z-filopodia were typically oriented in the direction of axon growth, not attached to the substratum, protruded spontaneously without microtubule invasion, and had a lifetime that was considerably shorter than that of conventional filopodia. Z-filopodia formation and dynamics were regulated by actin-regulatory proteins, such as vasodilator-stimulated phosphoprotein, fascin, and cofilin. Chromophore-assisted laser inactivation of cofilin induced the rapid turnover of z-filopodia. An axon guidance receptor, neuropilin-1, was concentrated in z-filopodia and was transported together with them, whereas its ligand, semaphorin-3A, was selectively bound to them. Membrane domains associated with z-filopodia were also specialized and resembled those of lipid rafts, and their behaviors were closely related to those of neuropilin-1. The results suggest that z-filopodia have unique turnover properties, and unlike xy-filopodia, do not function as force-generating structures for axon extension.
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Affiliation(s)
- Motohiro Nozumi
- Department of Neurochemistry and Molecular Cell Biology, School of Medicine, and Graduate School of Medical/Dental Sciences, Niigata University, Niigata, Japan
| | - Yuta Sato
- Department of Neurochemistry and Molecular Cell Biology, School of Medicine, and Graduate School of Medical/Dental Sciences, Niigata University, Niigata, Japan
| | - Miyako Nishiyama-Usuda
- Department of Neurochemistry and Molecular Cell Biology, School of Medicine, and Graduate School of Medical/Dental Sciences, Niigata University, Niigata, Japan
| | - Michihiro Igarashi
- Department of Neurochemistry and Molecular Cell Biology, School of Medicine, and Graduate School of Medical/Dental Sciences, Niigata University, Niigata, Japan
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Deng C, Chen H. Brain-derived neurotrophic factor/tropomyosin receptor kinase B signaling in spinal muscular atrophy and amyotrophic lateral sclerosis. Neurobiol Dis 2024; 190:106377. [PMID: 38092270 DOI: 10.1016/j.nbd.2023.106377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2023] [Revised: 11/15/2023] [Accepted: 12/10/2023] [Indexed: 12/23/2023] Open
Abstract
Tropomyosin receptor kinase B (TrkB) and its primary ligand brain-derived neurotrophic factor (BDNF) are expressed in the neuromuscular system, where they affect neuronal survival, differentiation, and functions. Changes in BDNF levels and full-length TrkB (TrkB-FL) signaling have been revealed in spinal muscular atrophy (SMA) and amyotrophic lateral sclerosis (ALS), two common forms of motor neuron diseases that are characterized by defective neuromuscular junctions in early disease stages and subsequently progressive muscle weakness. This review summarizes the current understanding of BDNF/TrkB-FL-related research in SMA and ALS, with an emphasis on their alterations in the neuromuscular system and possible BDNF/TrkB-FL-targeting therapeutic strategies. The limitations of current studies and future directions are also discussed, giving the hope of discovering novel and effective treatments.
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Affiliation(s)
- Chunchu Deng
- Department of Rehabilitation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Hong Chen
- Department of Rehabilitation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
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Kropf E, Shekari A, Jaberi S, Puri A, Wu C, Fahnestock M. Age-induced nitrative stress decreases retrograde transport of proNGF via TrkA and increases proNGF retrograde transport and neurodegeneration via p75 NTR. Front Mol Neurosci 2023; 16:1241420. [PMID: 38025269 PMCID: PMC10679388 DOI: 10.3389/fnmol.2023.1241420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Accepted: 10/18/2023] [Indexed: 12/01/2023] Open
Abstract
Introduction Axonal transport of pro nerve growth factor (proNGF) is impaired in aged basal forebrain cholinergic neurons (BFCNs), which is associated with their degeneration. ProNGF is neurotrophic in the presence of its receptor tropomyosin-related kinase A (TrkA) but induces apoptosis via the pan-neurotrophin receptor (p75NTR) when TrkA is absent. It is well established that TrkA is lost while p75NTR is maintained in aged BFCNs, but whether aging differentially affects transport of proNGF via each receptor is unknown. Nitrative stress increases during aging, but whether age-induced nitrative stress differentially affects proNGF transport via TrkA versus p75NTR has not yet been studied. Answering these questions is essential for developing an accurate understanding of the mechanisms contributing to age-induced loss of proNGF transport and BFCN degeneration. Methods In this study, fluorescence microscopy was used to analyze axonal transport of quantum dot labeled proNGF in rat BFCNs in vitro. Receptor specific effects were studied with proNGF mutants that selectively bind to either TrkA (proNGF-KKE) or p75NTR (proNGF-Δ9-13). Signaling factor activity was quantified via immunostaining. Results Young BFCNs transported proNGF-KKE but not proNGF-Δ9-13, and proNGF transport was not different in p75NTR knockout BFCNs compared to wildtype BFCNs. These results indicate that young BFCNs transport proNGF via TrkA. In vitro aging increased transport of proNGF-Δ9-13 but decreased transport of proNGF-KKE. Treatment with the nitric oxide synthase inhibitor L-NAME reduced retrograde transport of proNGF-Δ9-13 in aged BFCNs while increasing retrograde transport of proNGF-KKE but did not affect TrkA or p75NTR levels. ProNGF-Δ9-13 induced greater pro-apoptotic signaling and neurodegeneration and less pro-survival signaling relative to proNGF-KKE. Discussion Together, these results indicate that age-induced nitrative stress decreases proNGF transport via TrkA while increasing proNGF transport via p75NTR. These transport deficits are associated with decreased survival signaling, increased apoptotic signaling, and neurodegeneration. Our findings elucidate the receptor specificity of age-and nitrative stress-induced proNGF transport deficits. These results may help to rescue the neurotrophic signaling of proNGF in aging to reduce age-induced loss of BFCN function and cognitive decline.
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Affiliation(s)
- Erika Kropf
- Neuroscience Program, McMaster University, Hamilton, ON, Canada
| | - Arman Shekari
- Neuroscience Program, McMaster University, Hamilton, ON, Canada
| | - Sama Jaberi
- Neuroscience Program, McMaster University, Hamilton, ON, Canada
| | - Anish Puri
- Neuroscience Program, McMaster University, Hamilton, ON, Canada
| | - Chengbiao Wu
- Department of Neurosciences, University of California San Diego, La Jolla, CA, United States
| | - Margaret Fahnestock
- Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, ON, Canada
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Martínez-Mármol R, Muhaisen A, Cotrufo T, Roselló-Busquets C, Ros O, Hernaiz-Llorens M, Pérez-Branguli F, Andrés RM, Parcerisas A, Pascual M, Ulloa F, Soriano E. Syntaxin-1 is necessary for UNC5A-C/Netrin-1-dependent macropinocytosis and chemorepulsion. Front Mol Neurosci 2023; 16:1253954. [PMID: 37829513 PMCID: PMC10565356 DOI: 10.3389/fnmol.2023.1253954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Accepted: 09/04/2023] [Indexed: 10/14/2023] Open
Abstract
Introduction Brain connectivity requires correct axonal guidance to drive axons to their appropriate targets. This process is orchestrated by guidance cues that exert attraction or repulsion to developing axons. However, the intricacies of the cellular machinery responsible for the correct response of growth cones are just being unveiled. Netrin-1 is a bifunctional molecule involved in axon pathfinding and cell migration that induces repulsion during postnatal cerebellar development. This process is mediated by UNC5 homolog receptors located on external granule layer (EGL) tracts. Methods Biochemical, imaging and cell biology techniques, as well as syntaxin-1A/B (Stx1A/B) knock-out mice were used in primary cultures and brain explants. Results and discussion Here, we demonstrate that this response is characterized by enhanced membrane internalization through macropinocytosis, but not clathrin-mediated endocytosis. We show that UNC5A, UNC5B, and UNC5C receptors form a protein complex with the t-SNARE syntaxin-1. By combining botulinum neurotoxins, an shRNA knock-down strategy and Stx1 knock-out mice, we demonstrate that this SNARE protein is required for Netrin1-induced macropinocytosis and chemorepulsion, suggesting that Stx1 is crucial in regulating Netrin-1-mediated axonal guidance.
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Affiliation(s)
- Ramón Martínez-Mármol
- Department of Cell Biology, Physiology and Immunology, Faculty of Biology and Institute of Neurosciences, Universitat de Barcelona (UB), Barcelona, Spain
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
| | - Ashraf Muhaisen
- Department of Cell Biology, Physiology and Immunology, Faculty of Biology and Institute of Neurosciences, Universitat de Barcelona (UB), Barcelona, Spain
- Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED-CIBER), ISCIII, Madrid, Spain
| | - Tiziana Cotrufo
- Department of Cell Biology, Physiology and Immunology, Faculty of Biology and Institute of Neurosciences, Universitat de Barcelona (UB), Barcelona, Spain
- Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED-CIBER), ISCIII, Madrid, Spain
| | - Cristina Roselló-Busquets
- Department of Cell Biology, Physiology and Immunology, Faculty of Biology and Institute of Neurosciences, Universitat de Barcelona (UB), Barcelona, Spain
| | - Oriol Ros
- Department of Cell Biology, Physiology and Immunology, Faculty of Biology and Institute of Neurosciences, Universitat de Barcelona (UB), Barcelona, Spain
| | - Marc Hernaiz-Llorens
- Department of Cell Biology, Physiology and Immunology, Faculty of Biology and Institute of Neurosciences, Universitat de Barcelona (UB), Barcelona, Spain
| | - Francesc Pérez-Branguli
- Department of Cell Biology, Physiology and Immunology, Faculty of Biology and Institute of Neurosciences, Universitat de Barcelona (UB), Barcelona, Spain
- IZKF Junior Research Group and BMBF Research Group Neuroscience, IZKF, Friedrich-Alexander-Universitaet Erlangen-Nuernberg, Erlangen, Germany
| | - Rosa Maria Andrés
- Department of Cell Biology, Physiology and Immunology, Faculty of Biology and Institute of Neurosciences, Universitat de Barcelona (UB), Barcelona, Spain
- Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED-CIBER), ISCIII, Madrid, Spain
| | - Antoni Parcerisas
- Tissue Repair and Regeneration Laboratory (TR2Lab), Institut de Recerca i Innovació en Ciències de la Vida i de la Salut a la Catalunya Central (IRIS-CC), Vic, Spain
- Biosciences Department, Faculty of Sciences, Technology and Engineerings, University of Vic - Central University of Catalonia (UVic-UCC), Vic, Spain
| | - Marta Pascual
- Department of Cell Biology, Physiology and Immunology, Faculty of Biology and Institute of Neurosciences, Universitat de Barcelona (UB), Barcelona, Spain
- Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED-CIBER), ISCIII, Madrid, Spain
| | - Fausto Ulloa
- Department of Cell Biology, Physiology and Immunology, Faculty of Biology and Institute of Neurosciences, Universitat de Barcelona (UB), Barcelona, Spain
- Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED-CIBER), ISCIII, Madrid, Spain
| | - Eduardo Soriano
- Department of Cell Biology, Physiology and Immunology, Faculty of Biology and Institute of Neurosciences, Universitat de Barcelona (UB), Barcelona, Spain
- Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED-CIBER), ISCIII, Madrid, Spain
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Gu X, Jia C, Wang J. Advances in Understanding the Molecular Mechanisms of Neuronal Polarity. Mol Neurobiol 2023; 60:2851-2870. [PMID: 36738353 DOI: 10.1007/s12035-023-03242-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 01/22/2023] [Indexed: 02/05/2023]
Abstract
The establishment and maintenance of neuronal polarity are important for neural development and function. Abnormal neuronal polarity establishment commonly leads to a variety of neurodevelopmental disorders. Over the past three decades, with the continuous development and improvement of biological research methods and techniques, we have made tremendous progress in the understanding of the molecular mechanisms of neuronal polarity establishment. The activity of positive and negative feedback signals and actin waves are both essential in this process. They drive the directional transport and aggregation of key molecules of neuronal polarity, promote the spatiotemporal regulation of ordered and coordinated interactions of actin filaments and microtubules, stimulate the specialization and growth of axons, and inhibit the formation of multiple axons. In this review, we focus on recent advances in these areas, in particular the important findings about neuronal polarity in two classical models, in vitro primary hippocampal/cortical neurons and in vivo cortical pyramidal neurons, and discuss our current understanding of neuronal polarity..
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Affiliation(s)
- Xi Gu
- Fujian Key Laboratory for Translational Research in Cancer and Neurodegenerative Diseases, Institute for Translational Medicine, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China.
| | - Chunhong Jia
- Department of Pediatrics, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.
| | - Junhao Wang
- Fujian Key Laboratory for Translational Research in Cancer and Neurodegenerative Diseases, Institute for Translational Medicine, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China
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Mahadik SS, Lundquist EA. TOM-1/tomosyn acts with the UNC-6/netrin receptor UNC-5 to inhibit growth cone protrusion in Caenorhabditis elegans. Development 2023; 150:dev201031. [PMID: 37014062 PMCID: PMC10112904 DOI: 10.1242/dev.201031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Accepted: 01/24/2023] [Indexed: 04/05/2023]
Abstract
In the polarity/protrusion model of growth cone repulsion from UNC-6/netrin, UNC-6 first polarizes the growth cone of the VD motor neuron axon via the UNC-5 receptor, and then regulates protrusion asymmetrically across the growth cone based on this polarity. UNC-6 stimulates protrusion dorsally through the UNC-40/DCC receptor, and inhibits protrusion ventrally through UNC-5, resulting in net dorsal growth. Previous studies showed that UNC-5 inhibits growth cone protrusion via the flavin monooxygenases and potential destabilization of F-actin, and via UNC-33/CRMP and restriction of microtubule plus-end entry into the growth cone. We show that UNC-5 inhibits protrusion through a third mechanism involving TOM-1/tomosyn. A short isoform of TOM-1 inhibited protrusion downstream of UNC-5, and a long isoform had a pro-protrusive role. TOM-1/tomosyn inhibits formation of the SNARE complex. We show that UNC-64/syntaxin is required for growth cone protrusion, consistent with a role of TOM-1 in inhibiting vesicle fusion. Our results are consistent with a model whereby UNC-5 utilizes TOM-1 to inhibit vesicle fusion, resulting in inhibited growth cone protrusion, possibly by preventing the growth cone plasma membrane addition required for protrusion.
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Affiliation(s)
- Snehal S. Mahadik
- Department of Molecular Biosciences, The University of Kansas, 1200 Sunnyside Avenue, 5049 Haworth Hall, Lawrence, KS 66045, USA
| | - Erik A. Lundquist
- Department of Molecular Biosciences, The University of Kansas, 1200 Sunnyside Avenue, 5049 Haworth Hall, Lawrence, KS 66045, USA
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Chandrasekaran A, Clarke A, McQueen P, Fang HY, Papoian GA, Giniger E. Computational simulations reveal that Abl activity controls cohesiveness of actin networks in growth cones. Mol Biol Cell 2022; 33:ar92. [PMID: 35857718 DOI: 10.1091/mbc.e21-11-0535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Extensive studies of growing axons have revealed many individual components and protein interactions that guide neuronal morphogenesis. Despite this, however, we lack any clear picture of the emergent mechanism by which this nanometer-scale biochemistry generates the multimicron-scale morphology and cell biology of axon growth and guidance in vivo. To address this, we studied the downstream effects of the Abl signaling pathway using a computer simulation software (MEDYAN) that accounts for mechanochemical dynamics of active polymers. Previous studies implicate two Abl effectors, Arp2/3 and Enabled, in Abl-dependent axon guidance decisions. We now find that Abl alters actin architecture primarily by activating Arp2/3, while Enabled plays a more limited role. Our simulations show that simulations mimicking modest levels of Abl activity bear striking similarity to actin profiles obtained experimentally from live imaging of actin in wild-type axons in vivo. Using a graph theoretical filament-filament contact analysis, moreover, we find that networks mimicking hyperactivity of Abl (enhanced Arp2/3) are fragmented into smaller domains of actin that interact weakly with each other, consistent with the pattern of actin fragmentation observed upon Abl overexpression in vivo. Two perturbative simulations further confirm that high-Arp2/3 actin networks are mechanically disconnected and fail to mount a cohesive response to perturbation. Taken together, these data provide a molecular-level picture of how the large-scale organization of the axonal cytoskeleton arises from the biophysics of actin networks.
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Affiliation(s)
- Aravind Chandrasekaran
- Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742.,National Institute of Neurological Diseases and Stroke, Bethesda, MD 20892
| | - Akanni Clarke
- National Institute of Neurological Diseases and Stroke, Bethesda, MD 20892.,Department of Biochemistry and Molecular Medicine, George Washington University School of Medicine/National Institutes of Health Graduate Partnerships Program, Washington, DC 20037
| | - Philip McQueen
- Center for Information Technology, National Institutes of Health, Bethesda, MD 20892
| | - Hsiao Yu Fang
- National Institute of Neurological Diseases and Stroke, Bethesda, MD 20892
| | - Garegin A Papoian
- Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742.,Institute for Physical Science and Technology, University of Maryland, College Park, MD 20742
| | - Edward Giniger
- National Institute of Neurological Diseases and Stroke, Bethesda, MD 20892
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Błaszczyk M, Gajewska M, Dymowska M, Majewska A, Domoradzki T, Prostek A, Pingwara R, Hulanicka M, Grzelkowska-Kowalczyk K. Interleukin-6 mimics insulin-dependent cellular distribution of some cytoskeletal proteins and Glut4 transporter without effect on glucose uptake in 3T3-L1 adipocytes. Histochem Cell Biol 2022; 157:525-546. [PMID: 35230485 DOI: 10.1007/s00418-022-02091-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/01/2022] [Indexed: 11/04/2022]
Abstract
Interleukin (IL)-6, a known proinflammatory cytokine, is released in both visceral adipose tissue and contracting skeletal muscle. In this study, we used microRNA profiling as a screening method to identify miRNA species modified by IL-6 treatment in mouse 3T3-L1 adipocytes. miRNA microarray analysis and qRT-PCR revealed increased expression of miR-146b-3p in adipocytes exposed to IL-6 (1 ng/ml) during 8-day differentiation. On the basis of ontological analysis of potential targets, selected proteins associated with cytoskeleton and transport were examined in the context of adipocyte response to insulin, using immunofluorescence and confocal microscopy. We concluded that IL-6: (i) does not affect insulin action on actin cellular distribution; (ii) modulates the effect of insulin on myosin light chain kinase (Mylk) distribution by preventing its shift toward cytoplasm; (iii) mimics the effect of insulin on dynein distribution by increasing its near-nuclear accumulation; (iv) mimics the effect of insulin on glucose transporter Glut4 distribution, especially by increasing its near-nuclear accumulation; (v) supports insulin action on early endosome marker Rab4A near-nuclear accumulation. Moreover, as IL-6 did not disturb insulin-dependent glucose uptake, our results do not confirm the IL-6-induced impairment of insulin action observed in some in vitro studies, suggesting that the effect of IL-6 is dose dependent.
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Affiliation(s)
- Maciej Błaszczyk
- Department of Physiological Sciences, Institute of Veterinary Medicine, Warsaw University of Life Sciences (SGGW), Nowoursynowska 159, 02-776, Warsaw, Poland
| | - Małgorzata Gajewska
- Department of Physiological Sciences, Institute of Veterinary Medicine, Warsaw University of Life Sciences (SGGW), Nowoursynowska 159, 02-776, Warsaw, Poland
| | - Marta Dymowska
- Department of Physiological Sciences, Institute of Veterinary Medicine, Warsaw University of Life Sciences (SGGW), Nowoursynowska 159, 02-776, Warsaw, Poland
| | - Alicja Majewska
- Department of Physiological Sciences, Institute of Veterinary Medicine, Warsaw University of Life Sciences (SGGW), Nowoursynowska 159, 02-776, Warsaw, Poland
| | - Tomasz Domoradzki
- Department of Physiological Sciences, Institute of Veterinary Medicine, Warsaw University of Life Sciences (SGGW), Nowoursynowska 159, 02-776, Warsaw, Poland
| | - Adam Prostek
- Department of Physiological Sciences, Institute of Veterinary Medicine, Warsaw University of Life Sciences (SGGW), Nowoursynowska 159, 02-776, Warsaw, Poland
| | - Rafał Pingwara
- Department of Physiological Sciences, Institute of Veterinary Medicine, Warsaw University of Life Sciences (SGGW), Nowoursynowska 159, 02-776, Warsaw, Poland
| | - Magdalena Hulanicka
- Department of Physiological Sciences, Institute of Veterinary Medicine, Warsaw University of Life Sciences (SGGW), Nowoursynowska 159, 02-776, Warsaw, Poland
| | - Katarzyna Grzelkowska-Kowalczyk
- Department of Physiological Sciences, Institute of Veterinary Medicine, Warsaw University of Life Sciences (SGGW), Nowoursynowska 159, 02-776, Warsaw, Poland.
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Agrawal M, Welshhans K. Local Translation Across Neural Development: A Focus on Radial Glial Cells, Axons, and Synaptogenesis. Front Mol Neurosci 2021; 14:717170. [PMID: 34434089 PMCID: PMC8380849 DOI: 10.3389/fnmol.2021.717170] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Accepted: 07/20/2021] [Indexed: 11/13/2022] Open
Abstract
In the past two decades, significant progress has been made in our understanding of mRNA localization and translation at distal sites in axons and dendrites. The existing literature shows that local translation is regulated in a temporally and spatially restricted manner and is critical throughout embryonic and post-embryonic life. Here, recent key findings about mRNA localization and local translation across the various stages of neural development, including neurogenesis, axon development, and synaptogenesis, are reviewed. In the early stages of development, mRNAs are localized and locally translated in the endfeet of radial glial cells, but much is still unexplored about their functional significance. Recent in vitro and in vivo studies have provided new information about the specific mechanisms regulating local translation during axon development, including growth cone guidance and axon branching. Later in development, localization and translation of mRNAs help mediate the major structural and functional changes that occur in the axon during synaptogenesis. Clinically, changes in local translation across all stages of neural development have important implications for understanding the etiology of several neurological disorders. Herein, local translation and mechanisms regulating this process across developmental stages are compared and discussed in the context of function and dysfunction.
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Affiliation(s)
- Manasi Agrawal
- School of Biomedical Sciences, Kent State University, Kent, OH, United States
| | - Kristy Welshhans
- Department of Biological Sciences, University of South Carolina, Columbia, SC, United States
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RHOA signaling defects result in impaired axon guidance in iPSC-derived neurons from patients with tuberous sclerosis complex. Nat Commun 2021; 12:2589. [PMID: 33972524 PMCID: PMC8110792 DOI: 10.1038/s41467-021-22770-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Accepted: 03/26/2021] [Indexed: 11/30/2022] Open
Abstract
Patients with Tuberous Sclerosis Complex (TSC) show aberrant wiring of neuronal connections formed during development which may contribute to symptoms of TSC, such as intellectual disabilities, autism, and epilepsy. Yet models examining the molecular basis for axonal guidance defects in developing human neurons have not been developed. Here, we generate human induced pluripotent stem cell (hiPSC) lines from a patient with TSC and genetically engineer counterparts and isogenic controls. By differentiating hiPSCs, we show that control neurons respond to canonical guidance cues as predicted. Conversely, neurons with heterozygous loss of TSC2 exhibit reduced responses to several repulsive cues and defective axon guidance. While TSC2 is a known key negative regulator of MTOR-dependent protein synthesis, we find that TSC2 signaled through MTOR-independent RHOA in growth cones. Our results suggest that neural network connectivity defects in patients with TSC may result from defects in RHOA-mediated regulation of cytoskeletal dynamics during neuronal development. Patients with Tuberous Sclerosis Complex (TSC) show aberrant wiring of neuronal connections. Here, the authors generate iPSC-derived neurons from patients with TSC. TSC2 +/− neurons show impaired mTOR-independent RhoA signaling-mediated axon guidance.
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11
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Senra D, Páez A, Gueron G, Bruno L, Guisoni N. Following the footprints of variability during filopodial growth. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2020; 49:643-659. [PMID: 33141270 DOI: 10.1007/s00249-020-01473-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 10/06/2020] [Accepted: 10/19/2020] [Indexed: 01/09/2023]
Abstract
Filopodia are actin-built finger-like dynamic structures that protrude from the cell cortex. These structures can sense the environment and play key roles in migration and cell-cell interactions. The growth-retraction cycle of filopodia is a complex process exquisitely regulated by intra- and extra-cellular cues, whose nature remains elusive. Filopodia present wide variation in length, lifetime and growth rate. Here, we investigate the features of filopodia patterns in fixed prostate tumor cells by confocal microscopy. Analysis of almost a thousand filopodia suggests the presence of two different populations: one characterized by a narrow distribution of lengths and the other with a much more variable pattern with very long filopodia. We explore a stochastic model of filopodial growth which takes into account diffusion and reactions involving actin and the regulatory proteins formin and capping, and retrograde flow. Interestingly, we found an inverse dependence between the filopodial length and the retrograde velocity. This result led us to propose that variations in the retrograde velocity could explain the experimental lengths observed for these tumor cells. In this sense, one population involves a wider range of retrograde velocities than the other population, and also includes low values of this velocity. It has been hypothesized that cells would be able to regulate retrograde flow as a mechanism to control filopodial length. Thus, we propound that the experimental filopodia pattern is the result of differential retrograde velocities originated from heterogeneous signaling due to cell-substrate interactions or prior cell-cell contacts.
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Affiliation(s)
- Daniela Senra
- Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas, Universidad Nacional de La Plata, CONICET, La Plata, Argentina
| | - Alejandra Páez
- Laboratorio de Inflamación y Cáncer, Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, C1428EGA, Buenos Aires, Argentina
- CONICET, Universidad de Buenos Aires, Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN), C1428EGA, Buenos Aires, Argentina
- Unidad de Transferencia Genética, Instituto de Oncología "Ángel H. Roffo", Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Geraldine Gueron
- Laboratorio de Inflamación y Cáncer, Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, C1428EGA, Buenos Aires, Argentina
- CONICET, Universidad de Buenos Aires, Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN), C1428EGA, Buenos Aires, Argentina
| | - Luciana Bruno
- Instituto de Cálculo, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, CONICET, Pabellón 2, Ciudad Universitaria (1428), Buenos Aires, Argentina
| | - Nara Guisoni
- Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas, Universidad Nacional de La Plata, CONICET, La Plata, Argentina.
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12
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A Cdc42-mediated supracellular network drives polarized forces and Drosophila egg chamber extension. Nat Commun 2020; 11:1921. [PMID: 32317641 PMCID: PMC7174421 DOI: 10.1038/s41467-020-15593-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Accepted: 03/13/2020] [Indexed: 01/09/2023] Open
Abstract
Actomyosin supracellular networks emerge during development and tissue repair. These cytoskeletal structures are able to generate large scale forces that can extensively remodel epithelia driving tissue buckling, closure and extension. How supracellular networks emerge, are controlled and mechanically work still remain elusive. During Drosophila oogenesis, the egg chamber elongates along the anterior-posterior axis. Here we show that a dorsal-ventral polarized supracellular F-actin network, running around the egg chamber on the basal side of follicle cells, emerges from polarized intercellular filopodia that radiate from basal stress fibers and extend penetrating neighboring cell cortexes. Filopodia can be mechanosensitive and function as cell-cell anchoring sites. The small GTPase Cdc42 governs the formation and distribution of intercellular filopodia and stress fibers in follicle cells. Finally, our study shows that a Cdc42-dependent supracellular cytoskeletal network provides a scaffold integrating local oscillatory actomyosin contractions at the tissue scale to drive global polarized forces and tissue elongation. During development, organs undergo large scale forces driven by the cytoskeleton but the precise molecular regulation of cytoskeletal networks remains unclear. Here, the authors report a Cdc42-dependent supracellular cytoskeletal network integrates local actomyosin contraction at tissue scale and drives global tissue elongation.
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13
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Milewska M, Domoradzki T, Majewska A, Błaszczyk M, Gajewska M, Hulanicka M, Grzelkowska-Kowalczyk K. Interleukin-6 affects pacsin3, ephrinA4 expression and cytoskeletal proteins in differentiating primary skeletal myoblasts through transcriptional and post-transcriptional mechanisms. Cell Tissue Res 2019; 380:155-172. [PMID: 31820147 DOI: 10.1007/s00441-019-03133-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Accepted: 10/29/2019] [Indexed: 12/18/2022]
Abstract
Interleukin (IL)-6 is a proinflammatory cytokine released in injured and contracting skeletal muscles. In this study, we examined cellular expression of proteins associated with cytoskeleton organization and cell migration, chosen on the basis of microRNA profiling, in rat primary skeletal muscle cells (RSkMC) treated with IL-6 (1 ng/ml) for 11 days. MiRNA microarray analysis and qRT-PCR revealed increased expression of miR-154-3p and miR-338-3p in muscle cells treated with IL-6. Pacsin3 was downregulated post-transcriptionally by IL-6, but not by IGF-I. Ephrin4A protein was increased both in IL-6- and IGF-I-treated myocytes. IL-6, but not IGF-I, stimulated migratory ability of RSkMC, examined in wound healing assay. Alpha-actinin protein was slightly augmented in RSKMC treated with IL-6, similarly to IGF-I. IL-6, but not IGF-I, upregulated desmin in differentiating RSkMC. IL-6 supplementation caused accumulation of alpha-actinin and desmin in near-nuclear area of muscle cells, which was manifested by increased ratio: mean near-nuclear fluorescence/mean peripheral cytoplasm fluorescence of these proteins. We concluded that IL-6, a known proinflammatory cytokine and a physical activity-associated myokine, acting during differentiation of primary skeletal muscle cells, alters expression of nonmuscle-specific miRNAs. This cytokine causes differential effects on pacsin-3 and ephrinA4, through post-transcriptional inhibition and stimulation, respectively. IL-6-exerted modifications of cytoskeletal proteins in muscle cells include both transcriptional (desmin and dynein heavy chain 5) and post-transcriptional activation (alpha-actinin). Moreover, IL-6 augments near-nuclear distribution of cytoskeletal proteins, alpha-actinin and desmin and promotes migration of myocytes. Such effects suggest that IL-6 plays a role during skeletal muscle regeneration, acting through mechanisms independent of regulation of myogenic program.
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Affiliation(s)
- Marta Milewska
- Institute of Veterinary Medicine, Department of Physiological Sciences, Warsaw University of Life Sciences (SGGW), Nowoursynowska 159, 02-776, Warsaw, Poland
| | - Tomasz Domoradzki
- Institute of Veterinary Medicine, Department of Physiological Sciences, Warsaw University of Life Sciences (SGGW), Nowoursynowska 159, 02-776, Warsaw, Poland
| | - Alicja Majewska
- Institute of Veterinary Medicine, Department of Physiological Sciences, Warsaw University of Life Sciences (SGGW), Nowoursynowska 159, 02-776, Warsaw, Poland
| | - Maciej Błaszczyk
- Institute of Veterinary Medicine, Department of Physiological Sciences, Warsaw University of Life Sciences (SGGW), Nowoursynowska 159, 02-776, Warsaw, Poland
| | - Małgorzata Gajewska
- Institute of Veterinary Medicine, Department of Physiological Sciences, Warsaw University of Life Sciences (SGGW), Nowoursynowska 159, 02-776, Warsaw, Poland
| | - Magdalena Hulanicka
- Institute of Veterinary Medicine, Department of Physiological Sciences, Warsaw University of Life Sciences (SGGW), Nowoursynowska 159, 02-776, Warsaw, Poland
| | - Katarzyna Grzelkowska-Kowalczyk
- Institute of Veterinary Medicine, Department of Physiological Sciences, Warsaw University of Life Sciences (SGGW), Nowoursynowska 159, 02-776, Warsaw, Poland.
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14
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Ahmed S, Kim Y. PGE 2 mediates cytoskeletal rearrangement of hemocytes via Cdc42, a small G protein, to activate actin-remodeling factors in Spodoptera exigua (Lepidoptera: Noctuidae). ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2019; 102:e21607. [PMID: 31338878 DOI: 10.1002/arch.21607] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 07/09/2019] [Accepted: 07/10/2019] [Indexed: 06/10/2023]
Abstract
Prostaglandin E2 (PGE2 ) mediates cellular immune responses in insects by stimulating hemocyte-spreading behavior that is driven by actin remodeling to form filopodial or lamellipodial cytoplasmic extensions. In Spodoptera exigua (Lepidoptera: Noctuidae), Cdc42, a small G protein, played a crucial role in mediating PGE2 signal on hemocyte-spreading behavior. Hemocyte-spreading behavior requires actin cytoskeletal rearrangement. A plethora of actin-related proteins have been predicted to have functional links with Cdc42. Here, we selected four actin-associated genes (Actin-related protein 2 [Arp2], Profilin, Cofilin, and Fascin) and evaluated their influences on cytoskeletal rearrangement in S. exigua. Bioinformatic analysis confirmed their gene identities. Transcript analysis using reverse-transcription polymerase chain reaction indicated that all four actin-associated genes were expressed in most developmental stages, showing high expression levels in larval hemocytes. RNA interference (RNAi) against these genes was performed by injecting double-stranded RNA (dsRNA) to hemocoel. Under RNAi condition, the hemocyte-spreading behavior was significantly impaired except for dsRNA treatment against Cofilin, an actin-depolymerizing factor. Alteration of cytoskeletal rearrangement appeared to vary after different RNAi treatments. RNAi against Arp2 markedly suppressed lamellipodial extension while RNAi against Profilin or Fascin adversely influenced filopodial extension. RNAi of these actin-associated factors prevented cellular immune responses measured by nodule formation against bacterial challenge. Under RNAi conditions, addition of PGE2 did not well induce hemocyte-spreading behavior, suggesting that these actin-associated factors might act downstream of the hormone signaling pathway. These results suggest that PGE2 can mediate hemocyte-spreading behavior via Cdc42 to activate downstream actin polymerization/branching/bundling factors, thus inducing actin cytoskeletal rearrangement.
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Affiliation(s)
- Shabbir Ahmed
- Department of Plant Medicals, College of Life Sciences, Andong National University, Andong, Korea
| | - Yonggyun Kim
- Department of Plant Medicals, College of Life Sciences, Andong National University, Andong, Korea
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15
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Thomason EJ, Escalante M, Osterhout DJ, Fuss B. The oligodendrocyte growth cone and its actin cytoskeleton: A fundamental element for progenitor cell migration and CNS myelination. Glia 2019; 68:1329-1346. [PMID: 31696982 DOI: 10.1002/glia.23735] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 09/26/2019] [Accepted: 10/01/2019] [Indexed: 01/06/2023]
Abstract
Cells of the oligodendrocyte (OLG) lineage engage in highly motile behaviors that are crucial for effective central nervous system (CNS) myelination. These behaviors include the guided migration of OLG progenitor cells (OPCs), the surveying of local environments by cellular processes extending from differentiating and pre-myelinating OLGs, and during the process of active myelin wrapping, the forward movement of the leading edge of the myelin sheath's inner tongue along the axon. Almost all of these motile behaviors are driven by actin cytoskeletal dynamics initiated within a lamellipodial structure that is located at the tip of cellular OLG/OPC processes and is structurally as well as functionally similar to the neuronal growth cone. Accordingly, coordinated stoichiometries of actin filament (F-actin) assembly and disassembly at these OLG/OPC growth cones have been implicated in directing process outgrowth and guidance, and the initiation of myelination. Nonetheless, the functional importance of the OLG/OPC growth cone still remains to be fully understood, and, as a unique aspect of actin cytoskeletal dynamics, F-actin depolymerization and disassembly start to predominate at the transition from myelination initiation to myelin wrapping. This review provides an overview of the current knowledge about OLG/OPC growth cones, and it proposes a model in which actin cytoskeletal dynamics in OLG/OPC growth cones are a main driver for morphological transformations and motile behaviors. Remarkably, these activities, at least at the later stages of OLG maturation, may be regulated independently from the transcriptional gene expression changes typically associated with CNS myelination.
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Affiliation(s)
- Elizabeth J Thomason
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of Medicine, Richmond, Virginia
| | - Miguel Escalante
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of Medicine, Richmond, Virginia.,Departamento de Toxicología, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Ciudad de México, Mexico
| | - Donna J Osterhout
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York
| | - Babette Fuss
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of Medicine, Richmond, Virginia
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16
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Wang W, Halasz E, Townes-Anderson E. Actin Dynamics, Regulated by RhoA-LIMK-Cofilin Signaling, Mediates Rod Photoreceptor Axonal Retraction After Retinal Injury. Invest Ophthalmol Vis Sci 2019; 60:2274-2285. [PMID: 31112612 PMCID: PMC6530517 DOI: 10.1167/iovs.18-26077] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Purpose Retraction of the axon terminals of rod photoreceptors after retinal detachment breaks the first synapse in the visual pathway, resulting in visual impairment. Previous work showed that the mechanism of axonal retraction involves RhoA signaling and its downstream effector LIM Kinase (LIMK) activation. We examined the response of the downstream component cofilin, a direct binding protein of actin filaments, as well as the regulation by RhoA-LIMK-Cofilin signaling of actin assembly/disassembly, in the presynaptic ribbon terminal of injured rod cells. Methods Injury was produced by retinal detachment or rod cell isolation. Detached porcine retina was probed for levels and localization of phosphorylated cofilin with Western blots and confocal microscopy, whereas rod cell cultures of dissociated salamander retina were examined for filamentous actin assembly/disassembly with a barbed end assay and phalloidin staining. Results A detachment increased phosphorylation of cofilin in retinal explants; phosphorylation occurred in rod terminals in sections of detached retina. Isolation of rod cells resulted in axon retraction accompanied by an increase in actin barbed ends and a decrease in net filament labeling. All changes were significantly reduced by either Rho kinase (ROCK) or LIMK inhibition, using Y27632 or BMS-5, respectively. Cytochalasin D also reduced retraction and stabilized filaments in isolated rod cells. Conclusions These results indicate that actin depolymerization via activation of RhoA downstream kinases and cofilin contributes to axon retraction. Preventing depolymerization, in addition to actomyosin contraction, may stabilize ribbon synapses after trauma.
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Affiliation(s)
- Weiwei Wang
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Graduate School of Biomedical Sciences, Rutgers Biomedical and Health Sciences, Rutgers, The State University of New Jersey, Newark, New Jersey, United States
| | - Eva Halasz
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Graduate School of Biomedical Sciences, Rutgers Biomedical and Health Sciences, Rutgers, The State University of New Jersey, Newark, New Jersey, United States
| | - Ellen Townes-Anderson
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Graduate School of Biomedical Sciences, Rutgers Biomedical and Health Sciences, Rutgers, The State University of New Jersey, Newark, New Jersey, United States
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17
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Liu L, Jiang H, Zhao W, Meng Y, Li J, Huang T, Sun J. Cdc42-mediated supracellular cytoskeleton induced cancer cell migration under low shear stress. Biochem Biophys Res Commun 2019; 519:134-140. [PMID: 31477271 DOI: 10.1016/j.bbrc.2019.08.149] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 08/26/2019] [Indexed: 01/29/2023]
Abstract
Tumor microenvironment is composed of biological, chemical and physical factors. Mechanical factors are more and more focused these years. Therefore, mimicking mechanical factors' contribution to cancer cell malignancy will greatly improve the advance in this field. Although the induced malignant behaviors are present under many stimuli such as growth or inflammatory factors, the cell key physical migration mechanisms are still missing. In this study, we identify that low shear stress significantly promotes the formation of needle-shaped membrane protrusions, which is called filopodia and important for the sense and interact of a cell with extracellular matrix in the tumor microenvironment. Under low shear stress, the migration is promoted while it is inhibited in the presence of ROCK inhibitor Y27632, which could abolish the F-actin network. Using cell imaging, we further unravel that key to these protrusions is Cell division cycle 42 (Cdc42) dependent. After Cdc42 activation, the filopodia is more and longer, acting as massagers to pass the information from a cell to the microenvironment for its malignant phenotype. In the Cdc42 inhibition, the filopodia is greatly reduced. Moreover, small GTPases Cdc42 rather than Rac1 and Rho directly controls the filopodia formation. Our work highlights that low shear stress and Cdc42 activation are sufficient to promote filopodia formation, it not only points out the novel structure for cancer progression but also provides the experimental physical basis for the efficient drug anti-cancer strategies.
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Affiliation(s)
- Lingling Liu
- School of Laboratory Medicine, Collaborative Innovation Center of Sichuan for Elderly Care and Health, Development and Regeneration Key Laboratory of Sichuan Province, Sichuan Provincial Engineering Laboratory for Prevention and Control Technology of Veterinary Drug Residue in Animal-origin Food, Chengdu Medical College, Chengdu, 610500, Sichuan, China
| | - Hua Jiang
- Department of Pediatrics, Department of Microbiology and Immunology, Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Wei Zhao
- School of Laboratory Medicine, Collaborative Innovation Center of Sichuan for Elderly Care and Health, Development and Regeneration Key Laboratory of Sichuan Province, Sichuan Provincial Engineering Laboratory for Prevention and Control Technology of Veterinary Drug Residue in Animal-origin Food, Chengdu Medical College, Chengdu, 610500, Sichuan, China
| | - Yao Meng
- School of Laboratory Medicine, Collaborative Innovation Center of Sichuan for Elderly Care and Health, Development and Regeneration Key Laboratory of Sichuan Province, Sichuan Provincial Engineering Laboratory for Prevention and Control Technology of Veterinary Drug Residue in Animal-origin Food, Chengdu Medical College, Chengdu, 610500, Sichuan, China
| | - Ji Li
- Department of Clinical Laboratory, Sichuan GEM Flower Hospital, Chengdu, 610213, Sichuan, PR China
| | - Tongwei Huang
- Department of Blood Transfusion, Ziyang Hospital of Traditional Chinese Medicine, Ziyang, 641300, Sichuan, PR China
| | - Jinghui Sun
- School of Laboratory Medicine, Collaborative Innovation Center of Sichuan for Elderly Care and Health, Development and Regeneration Key Laboratory of Sichuan Province, Sichuan Provincial Engineering Laboratory for Prevention and Control Technology of Veterinary Drug Residue in Animal-origin Food, Chengdu Medical College, Chengdu, 610500, Sichuan, China.
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18
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Li H, Wang Y, Hu X, Ma B, Zhang H. Thymosin beta 4 attenuates oxidative stress-induced injury of spinal cord-derived neural stem/progenitor cells through the TLR4/MyD88 pathway. Gene 2019; 707:136-142. [PMID: 31054361 DOI: 10.1016/j.gene.2019.04.083] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 04/28/2019] [Accepted: 04/30/2019] [Indexed: 01/22/2023]
Abstract
Neural stem/progenitor cells (NSPCs) can enhance regeneration after spinal cord injury (SCI), but survival of transplanted cells remains poor. Understanding how NSPCs respond to the chemical mediators of secondary injury thus is essential for treating SCI. Thymosin β4 (Tβ4) has physiological functions that are highly relevant to SCI. We exposed NSPCs to oxidative stress and found reduced expression of Tβ4 in H2O2-injured NSPCs. Using an MTT assay, we found that Tβ4 dose dependently increased viability of the injured NSPCs. Tβ4 also reversed the decreases of intracellular Ca2+ concentration and increases of lactate dehydrogenase in NSPCs induced by H2O2 treatment. H2O2 exposure increased NSPC apoptosis, which Tβ4 decreased. In H2O2-induced NSPCs, ROS production and pro-inflammatory cytokines increased, and again, Tβ4 reversed these effects. We investigated the toll-like receptor 4 (TLR4) and myeloid differentiation primary response 88 (MyD88) signaling pathway as an underlying mechanism in Tβ4's protective effect on H2O2-exposed NSPCs. Our results showed that Tβ4 reduced expression of TLR4 and MyD88. Moreover, H2O2-exposed NSPCs that were treated with the TLR4/MyD88 pathway inhibitor showed a reversal of all the effects caused by H2O2, similar to Tβ4's effects. In conclusion, our study determined that Tβ4 attenuated H2O2-induced oxidative stress injury in NSPCs via the TLR4/MyD88 pathway.
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Affiliation(s)
- Hongwei Li
- Department of Spine SurgAery, Lanzhou University Second Hospital, Lanzhou 740030, Gansu, China
| | - Yonggang Wang
- Department of Spine SurgAery, Lanzhou University Second Hospital, Lanzhou 740030, Gansu, China
| | - Xuchang Hu
- Department of Spine SurgAery, Lanzhou University Second Hospital, Lanzhou 740030, Gansu, China
| | - Bing Ma
- Department of Spine SurgAery, Lanzhou University Second Hospital, Lanzhou 740030, Gansu, China
| | - Haihong Zhang
- Department of Spine SurgAery, Lanzhou University Second Hospital, Lanzhou 740030, Gansu, China.
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19
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Fuschini G, Cotrufo T, Ros O, Muhaisen A, Andrés R, Comella JX, Soriano E. Syntaxin-1/TI-VAMP SNAREs interact with Trk receptors and are required for neurotrophin-dependent outgrowth. Oncotarget 2018; 9:35922-35940. [PMID: 30542508 PMCID: PMC6267591 DOI: 10.18632/oncotarget.26307] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Accepted: 10/24/2018] [Indexed: 01/19/2023] Open
Abstract
SNARE proteins are essential components of the machinery that regulates vesicle trafficking and exocytosis. Their role is critical for the membrane-fusion processes that occur during neurotransmitter release. However, research in the last decade has also unraveled the relevance of these proteins in membrane expansion and cytoskeletal rearrangements during developmental processes such as neuronal migration and growth cone extension and attraction. Neurotrophins are neurotrophic factors that are required for many cellular functions throughout the brain, including neurite outgrowth and guidance, synaptic formation, and plasticity. Here we show that neurotrophin Trk receptors form a specific protein complex with the t-SNARE protein Syntaxin 1, both in vivo and in vitro. We also demonstrate that blockade of Syntaxin 1 abolishes neurotrophin-dependent growth of axons in neuronal cultures and decreases exocytotic events at the tip of axonal growth cones. 25-kDa soluble N-ethylmaleimide-sensitive factor attachment protein and Vesicle-associated membrane protein 2 do not participate in the formation of this SNARE complex, while tetanus neurotoxin-insensitive vesicle-associated membrane protein interacts with Trk receptors; knockdown of this (v) SNARE impairs Trk-dependent outgrowth. Taken together, our results support the notion that an atypical SNARE complex comprising Syntaxin 1 and tetanus neurotoxin-insensitive vesicle-associated membrane protein is required for axonal neurotrophin function.
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Affiliation(s)
- Giulia Fuschini
- Department of Cell Biology, Physiology and Immunology, Faculty of Biology, University of Barcelona, 08028 Barcelona, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), ISCIII, 28031 Madrid, Spain
| | - Tiziana Cotrufo
- Department of Cell Biology, Physiology and Immunology, Faculty of Biology, University of Barcelona, 08028 Barcelona, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), ISCIII, 28031 Madrid, Spain
- Vall d'Hebron Institute of Research (VHIR), 08035 Barcelona, Spain
| | - Oriol Ros
- Department of Cell Biology, Physiology and Immunology, Faculty of Biology, University of Barcelona, 08028 Barcelona, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), ISCIII, 28031 Madrid, Spain
| | - Ashraf Muhaisen
- Department of Cell Biology, Physiology and Immunology, Faculty of Biology, University of Barcelona, 08028 Barcelona, Spain
- Vall d'Hebron Institute of Research (VHIR), 08035 Barcelona, Spain
| | - Rosa Andrés
- Department of Cell Biology, Physiology and Immunology, Faculty of Biology, University of Barcelona, 08028 Barcelona, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), ISCIII, 28031 Madrid, Spain
| | - Joan X. Comella
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), ISCIII, 28031 Madrid, Spain
- Vall d'Hebron Institute of Research (VHIR), 08035 Barcelona, Spain
| | - Eduardo Soriano
- Department of Cell Biology, Physiology and Immunology, Faculty of Biology, University of Barcelona, 08028 Barcelona, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), ISCIII, 28031 Madrid, Spain
- Vall d'Hebron Institute of Research (VHIR), 08035 Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), 08010 Barcelona, Spain
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20
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Chakrabarty N, Dubey P, Tang Y, Ganguly A, Ladt K, Leterrier C, Jung P, Roy S. Processive flow by biased polymerization mediates the slow axonal transport of actin. J Cell Biol 2018; 218:112-124. [PMID: 30401699 PMCID: PMC6314539 DOI: 10.1083/jcb.201711022] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2017] [Revised: 09/02/2018] [Accepted: 10/25/2018] [Indexed: 12/15/2022] Open
Abstract
Chakrabarty et al. propose a model in which slow axonal transport of actin can occur by a biased polymerization of actin filaments along the axon shaft without the involvement of microtubules (MTs) or MT-based motors. These dynamics are distinct from polymer sliding—the canonical mechanism thought to convey cytoskeletal cargoes in slow transport. Classic pulse-chase studies have shown that actin is conveyed in slow axonal transport, but the mechanistic basis for this movement is unknown. Recently, we reported that axonal actin was surprisingly dynamic, with focal assembly/disassembly events (“actin hotspots”) and elongating polymers along the axon shaft (“actin trails”). Using a combination of live imaging, superresolution microscopy, and modeling, in this study, we explore how these dynamic structures can lead to processive transport of actin. We found relatively more actin trails elongated anterogradely as well as an overall slow, anterogradely biased flow of actin in axon shafts. Starting with first principles of monomer/filament assembly and incorporating imaging data, we generated a quantitative model simulating axonal hotspots and trails. Our simulations predict that the axonal actin dynamics indeed lead to a slow anterogradely biased flow of the population. Collectively, the data point to a surprising scenario where local assembly and biased polymerization generate the slow axonal transport of actin without involvement of microtubules (MTs) or MT-based motors. Mechanistically distinct from polymer sliding, this might be a general strategy to convey highly dynamic cytoskeletal cargoes.
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Affiliation(s)
- Nilaj Chakrabarty
- Department of Physics and Astronomy, Neuroscience Program and Quantitative Biology Institute, Ohio University, Athens, OH
| | - Pankaj Dubey
- Department of Pathology and Laboratory Medicine, University of Wisconsin-Madison, Madison, WI
| | - Yong Tang
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA
| | - Archan Ganguly
- Department of Neurosciences, University of California, San Diego, La Jolla, CA
| | - Kelsey Ladt
- Department of Neurosciences, University of California, San Diego, La Jolla, CA
| | - Christophe Leterrier
- Aix-Marseille Université, Centre National de la Recherche Scientifique, Institut Neurophysiopathol, NeuroCyto, Marseille, France
| | - Peter Jung
- Department of Physics and Astronomy, Neuroscience Program and Quantitative Biology Institute, Ohio University, Athens, OH
| | - Subhojit Roy
- Department of Pathology and Laboratory Medicine, University of Wisconsin-Madison, Madison, WI .,Department of Neuroscience, University of Wisconsin-Madison, Madison, WI
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21
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Rosas NM, Alvarez Juliá A, Alzuri SE, Frasch AC, Fuchsova B. Alanine Scanning Mutagenesis of the C-Terminal Cytosolic End of Gpm6a Identifies Key Residues Essential for the Formation of Filopodia. Front Mol Neurosci 2018; 11:314. [PMID: 30233315 PMCID: PMC6131581 DOI: 10.3389/fnmol.2018.00314] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Accepted: 08/15/2018] [Indexed: 12/14/2022] Open
Abstract
Neuronal membrane glycoprotein M6a (Gpm6a) is a protein with four transmembrane regions and the N- and the C-ends facing the cytosol. It functions in processes of neuronal development, outgrowth of neurites, and formation of filopodia, spines, and synapsis. Molecular mechanisms by which Gpm6a acts in these processes are not fully comprehended. Structural similarities of Gpm6a with tetraspanins led us to hypothesize that, similarly to tetraspanins, the cytoplasmic tails function as connections with cytoskeletal and/or signaling proteins. Here, we demonstrate that the C- but not the N-terminal cytosolic end of Gpm6a is required for the formation of filopodia by Gpm6a in cultured neurons from rat hippocampus and in neuroblastoma cells N2a. Further immunofluorescence microcopy and flow cytometry analysis show that deletion of neither the N- nor the C-terminal intracellular domains interferes with the recognition of Gpm6a by the function-blocking antibody directed against the extracellular part of Gpm6a. Expression levels of both truncation mutants were not affected but we observed decrease in the amount of both truncated proteins on cell surface suggesting that the incapacity of the Gpm6a lacking C-terminus to induce filopodium formation is not due to the lower amount of Gpm6a on cell surface. Following colocalization assays shows that deletion of the C- but not the N-terminus diminishes the association of Gpm6a with clathrin implying involvement of clathrin-mediated trafficking events. Next, using comprehensive alanine scanning mutagenesis of the C-terminus we identify K250, K255, and E258 as the key residues for the formation of filopodia by Gpm6a. Substitution of these charged residues with alanine also diminishes the amount of Gpm6a on cell surface and in case of K255 and E258 leads to the lower amount of total expressed protein. Subsequent bioinformatic analysis of Gpm6a amino acid sequence reveals that highly conserved and functional residues cluster preferentially within the C- and not within the N-terminus and that K250, K255, and E258 are predicted as part of sorting signals of transmembrane proteins. Altogether, our results provide evidence that filopodium outgrowth induced by Gpm6a requires functionally critical residues within the C-terminal cytoplasmic tail.
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Affiliation(s)
- Nicolás M Rosas
- Instituto de Investigaciones Biotecnológicas IIB-INTECH, CONICET-UNSAM, San Martin, Argentina
| | - Anabel Alvarez Juliá
- Instituto de Investigaciones Biotecnológicas IIB-INTECH, CONICET-UNSAM, San Martin, Argentina
| | - Sofia E Alzuri
- Instituto de Investigaciones Biotecnológicas IIB-INTECH, CONICET-UNSAM, San Martin, Argentina
| | - Alberto C Frasch
- Instituto de Investigaciones Biotecnológicas IIB-INTECH, CONICET-UNSAM, San Martin, Argentina
| | - Beata Fuchsova
- Instituto de Investigaciones Biotecnológicas IIB-INTECH, CONICET-UNSAM, San Martin, Argentina
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ROCK inhibition in models of neurodegeneration and its potential for clinical translation. Pharmacol Ther 2018; 189:1-21. [DOI: 10.1016/j.pharmthera.2018.03.008] [Citation(s) in RCA: 99] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Xu JD, Diao MQ, Niu GJ, Wang XW, Zhao XF, Wang JX. A Small GTPase, RhoA, Inhibits Bacterial Infection Through Integrin Mediated Phagocytosis in Invertebrates. Front Immunol 2018; 9:1928. [PMID: 30233567 PMCID: PMC6127615 DOI: 10.3389/fimmu.2018.01928] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Accepted: 08/06/2018] [Indexed: 12/14/2022] Open
Abstract
The Ras GTPase superfamily, including more than 100 members, plays a vital role in a number of cellular processes, such as cytoskeleton recombination, gene expression, and signaling pathway regulation. Some members of the superfamily participate in innate immunity in animals. However, there have been few studies of RhoA on this aspect. In the present study, we identified a RhoA GTPase in the shrimp Marsupenaeus japonicus and named it MjRhoA. Expression of MjRhoA was significantly upregulated in hemocytes and heart of shrimp challenged with Vibrio anguillarum. Overexpression of MjRhoA in shrimp caused the total bacterial number to decrease significantly and knockdown of MjRhoA increased the bacterial number obviously, with a consequent decline in shrimp survival. These results confirmed the antibacterial function of MjRhoA in shrimp. Further study showed that rate of phagocytosis of hemocytes was decreased in MjRhoA-knockdown shrimp. Interestingly, we observed that MjRhoA was translocated onto the hemocyte membrane at 1 h post V. anguillarum challenge. The expression levels of the β-integrin-mediated phagocytosis markers ROCK2 and Arp2/3 declined significantly after knockdown of MjRhoA. These results suggested that the antibacterial function of MjRhoA was related to β-integrin-mediated phagocytosis in shrimp. Our previous study identified that a C-type lectin, hFcLec4, initiated β-integrin mediated phagocytosis after bacterial infection. Thus, knockdown of hFcLec4 and β-integrin was performed. The results showed that the translocation of MjRhoA from the cytoplasm to membrane was inhibited and the expression level of MjRhoA was decreased, suggesting that MjRhoA participated in hFcLec4-integrin mediated phagocytosis. Therefore, our study identified a new hFcLec4-integrin-RhoA dependent phagocytosis against bacterial infection in shrimp.
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Affiliation(s)
- Ji-Dong Xu
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Sciences, Shandong University, Jinan, China
| | - Meng-Qi Diao
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Sciences, Shandong University, Jinan, China
| | - Guo-Juan Niu
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Sciences, Shandong University, Jinan, China
| | - Xian-Wei Wang
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Sciences, Shandong University, Jinan, China.,State Key Laboratory of Microbial Technology, Shandong University, Jinan, China
| | - Xiao-Fan Zhao
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Sciences, Shandong University, Jinan, China
| | - Jin-Xing Wang
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Sciences, Shandong University, Jinan, China.,State Key Laboratory of Microbial Technology, Shandong University, Jinan, China
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Roles of 5-HT on phase transition of neurite outgrowth in the identified serotoninergic neuron C1, Helisoma trivolvis. INVERTEBRATE NEUROSCIENCE 2018; 18:10. [PMID: 30128715 DOI: 10.1007/s10158-018-0214-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2018] [Accepted: 07/27/2018] [Indexed: 10/28/2022]
Abstract
Neurite outgrowth is a morphological marker of neuronal differentiation and neuroregeneration, and the process includes four essential phases, namely initiation, elongation, guidance and cessation. Intrinsic and extrinsic signaling molecules seem to involve morphological changes of neurite outgrowth via various cellular signaling cascades phase transition. Although mechanisms associated with neurite outgrowth have been studied extensively, little is known about how phase transition is regulated during neurite outgrowth. 5-HT has long been studied with regard to its relationship to neurite outgrowth in invertebrate and vertebrate culture systems, and many studies have suggested 5-HT inhibits neurite elongation and growth cone motility, in particular, at the growing parts of neurite such as growth cones and filopodia. However, the underlying mechanisms need to be investigated. In this study, we investigated roles of 5-HT on neurite outgrowth using single serotonergic neurons C1 isolated from Helisoma trivolvis. We observed that 5-HT delayed phase transitions from initiation to elongation of neurite outgrowth. This study for the first time demonstrated that 5-HT has a critical role in phase-controlling mechanisms of neurite outgrowth in neuronal cell cultures.
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25
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The transmembrane collagen COL-99 guides longitudinally extending axons in C. elegans. Mol Cell Neurosci 2018; 89:9-19. [DOI: 10.1016/j.mcn.2018.03.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 02/27/2018] [Accepted: 03/09/2018] [Indexed: 11/23/2022] Open
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Lee S, Esworthy T, Stake S, Miao S, Zuo YY, Harris BT, Zhang LG. Advances in 3D Bioprinting for Neural Tissue Engineering. ACTA ACUST UNITED AC 2018. [DOI: 10.1002/adbi.201700213] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Se‐Jun Lee
- Department of Mechanical and Aerospace Engineering George Washington University Washington DC 20052 USA
| | - Timothy Esworthy
- Department of Mechanical and Aerospace Engineering George Washington University Washington DC 20052 USA
| | - Seth Stake
- Department of Medicine George Washington University Washington DC 20052 USA
| | - Shida Miao
- Department of Mechanical and Aerospace Engineering George Washington University Washington DC 20052 USA
| | - Yi Y. Zuo
- Department of Mechanical Engineering University of Hawaii at Manoa Honolulu HI 96822 USA
| | - Brent T. Harris
- Department of Neurology and Pathology Georgetown University Washington DC 20007 USA
| | - Lijie Grace Zhang
- Department of Mechanical and Aerospace Engineering George Washington University Washington DC 20052 USA
- Department of Medicine George Washington University Washington DC 20052 USA
- Department of Biomedical Engineering George Washington University Washington DC 20052 USA
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Etxebeste O, Espeso EA. Neurons show the path: tip-to-nucleus communication in filamentous fungal development and pathogenesis. FEMS Microbiol Rev 2017; 40:610-24. [PMID: 27587717 DOI: 10.1093/femsre/fuw021] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/17/2016] [Indexed: 01/11/2023] Open
Abstract
Multiple fungal species penetrate substrates and accomplish host invasion through the fast, permanent and unidirectional extension of filamentous cells known as hyphae. Polar growth of hyphae results, however, in a significant increase in the distance between the polarity site, which also receives the earliest information about ambient conditions, and nuclei, where adaptive responses are executed. Recent studies demonstrate that these long distances are overcome by signal transduction pathways which convey sensory information from the polarity site to nuclei, controlling development and pathogenesis. The present review compares the striking connections of the mechanisms for long-distance communication in hyphae with those from neurons, and discusses the importance of their study in order to understand invasion and dissemination processes of filamentous fungi, and design strategies for developmental control in the future.
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Affiliation(s)
- Oier Etxebeste
- Biochemistry II laboratory, Department of Applied Chemistry, Faculty of Chemistry, University of the Basque Country (UPV/EHU), 20018 San Sebastian, Spain
| | - Eduardo A Espeso
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas (CSIC), Ramiro de Maeztu 9, 28040 Madrid, Spain
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Tseng YT, Jong YJ, Liang WF, Chang FR, Lo YC. The water extract of Liuwei dihuang possesses multi-protective properties on neurons and muscle tissue against deficiency of survival motor neuron protein. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2017; 34:97-105. [PMID: 28899515 DOI: 10.1016/j.phymed.2017.08.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 06/06/2017] [Accepted: 08/16/2017] [Indexed: 06/07/2023]
Abstract
BACKGROUND Deficiency of survival motor neuron (SMN) protein, which is encoded by the SMN1 and SMN2 genes, induces widespread splicing defects mainly in spinal motor neurons, and leads to spinal muscular atrophy (SMA). Currently, there is no effective treatment for SMA. Liuwei dihuang (LWDH), a traditional Chinese herbal formula, possesses multiple therapeutic benefits against various diseases via modulation of the nervous, immune and endocrine systems. Previously, we demonstrated water extract of LWDH (LWDH-WE) protects dopaminergic neurons and improves motor activity in models of Parkinson's disease. PURPOSE This study aimed to investigate the potential protection of LWDH-WE on SMN deficiency-induced neurodegeneration and muscle weakness. STUDY DESIGN The effects of LWDH-WE on SMN deficiency-induced neurotoxicity and muscle atrophy were examined by using SMN-deficient NSC34 motor neuron-like cells and SMA-like mice, respectively. METHODS Inducible SMN-knockdown NSC34 motor neuron-like cells were used to mimic SMN-deficient condition. Doxycycline (1 µg/ml) was used to induce SMN deficiency in stable NSC34 cell line carrying SMN-specific shRNA. SMAΔ7 mice were used as a severe type of SMA mouse model. Cell viability was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) and lactate dehydrogenase (LDH) assays. Apoptotic cells and neurite length were observed by inverted microscope. Protein expressions were examined by western blots. Muscle strength of animals was evaluated by hind-limb suspension test. RESULTS LWDH-WE significantly increased SMN protein level, mitochondrial membrane potential and cell viability of SMN-deficient NSC34 cells. LWDH-WE attenuated SMN deficiency-induced down-regulation of B-cell lymphoma-2 (Bcl-2) and up-regulation of cytosolic cytochrome c and cleaved caspase-3. Moreover, LWDH-WE prevented SMN deficiency-induced inhibition of neurite outgrowth and activation of Ras homolog gene family, member A (RhoA)/ Rho-associated protein kinase (ROCK2)/ phospho-LIM kinase (p-LIMK)/ phospho-cofilin (p-cofilin) pathway. Furthermore, in SMA-like mice, LWDH-WE improved muscle strength and body weight accompanied with up-regulation of SMN protein in spinal cord, brain, and gastrocnemius muscle tissues. CONCLUSION The present study demonstrated that LWDH-WE protects motor neurons against SMN deficiency-induced neurodegeneration, and it also improves the muscle strength of SMA-like mice, suggesting the potential benefits of LWDH-WE as a complementary prescription for SMN deficiency-related diseases.
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Affiliation(s)
- Yu-Ting Tseng
- Department of Pharmacology, College of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
| | - Yuh-Jyh Jong
- Graduate Institute of Clinical Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan; Departments of Pediatrics and Laboratory Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung 80708, Taiwan; Department of Biological Science and Technology, College of Biological Science and Technology, National Chiao Tung University, Hsinchu 30010, Taiwan
| | - Wei-Fang Liang
- Department of Pharmacology, College of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
| | - Fang-Rong Chang
- Graduate Institute of Natural Products, College of Pharmacy, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
| | - Yi-Ching Lo
- Department of Pharmacology, College of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan; Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan; Graduate Institute of Natural Products, College of Pharmacy, Kaohsiung Medical University, Kaohsiung 80708, Taiwan.
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Abstract
BACKGROUND Early postnatal exposure to general anesthetic agents causes a lasting impairment in learning and memory in animal models. One hypothesis to explain this finding is that exposure to anesthetic agents during critical points in neural development disrupts the formation of brain circuitry. Here, we explore the effects of sevoflurane on the neuronal growth cone, a specialization at the growing end of axons and dendrites that is responsible for the targeted growth that underlies connectivity between neurons. METHODS Dissociated neuronal cultures were prepared from embryonic mouse neocortex. Time-lapse images of live growth cones exposed to anesthetics were taken using differential interference contrast microscopy, and the rate of change of the area of the lamellipodia and the speed of the filopodial tip were quantified as measures of motility. The involvement of the p75 neurotropin receptor (p75NTR) was tested using inhibitors applied to the media and by a coimmunoprecipitation assay. RESULTS The rate of lamellipodial area change and filopodial tip velocity in both axonal and dendritic growth cones was significantly reduced with sevoflurane exposure between 2% and 6%. Motility could be substantially restored by treatment with Y27632 and TAT-peptide 5, which are inhibitors of Rho Kinase and p75NTR, respectively. Sevoflurane results in reduced coimmunoprecipitation of Rho-Guanosine-5'-diphosphate dissociation inhibitor after pulldown with p75NTR. CONCLUSIONS Sevoflurane interferes with growth cone motility, which is a critical process in brain circuitry formation. Our data suggest that this may occur through an action on the p75NTR, which promotes growth inhibitory signaling by the Rho pathway.
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Flavin monooxygenases regulate Caenorhabditis elegans axon guidance and growth cone protrusion with UNC-6/Netrin signaling and Rac GTPases. PLoS Genet 2017; 13:e1006998. [PMID: 28859089 PMCID: PMC5597259 DOI: 10.1371/journal.pgen.1006998] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 09/13/2017] [Accepted: 08/25/2017] [Indexed: 01/05/2023] Open
Abstract
The guidance cue UNC-6/Netrin regulates both attractive and repulsive axon guidance. Our previous work showed that in C. elegans, the attractive UNC-6/Netrin receptor UNC-40/DCC stimulates growth cone protrusion, and that the repulsive receptor, an UNC-5:UNC-40 heterodimer, inhibits growth cone protrusion. We have also shown that inhibition of growth cone protrusion downstream of the UNC-5:UNC-40 repulsive receptor involves Rac GTPases, the Rac GTP exchange factor UNC-73/Trio, and the cytoskeletal regulator UNC-33/CRMP, which mediates Semaphorin-induced growth cone collapse in other systems. The multidomain flavoprotein monooxygenase (FMO) MICAL (Molecule Interacting with CasL) also mediates growth cone collapse in response to Semaphorin by directly oxidizing F-actin, resulting in depolymerization. The C. elegans genome does not encode a multidomain MICAL-like molecule, but does encode five flavin monooxygenases (FMO-1, -2, -3, -4, and 5) and another molecule, EHBP-1, similar to the non-FMO portion of MICAL. Here we show that FMO-1, FMO-4, FMO-5, and EHBP-1 may play a role in UNC-6/Netrin directed repulsive guidance mediated through UNC-40 and UNC-5 receptors. Mutations in fmo-1, fmo-4, fmo-5, and ehbp-1 showed VD/DD axon guidance and branching defects, and variably enhanced unc-40 and unc-5 VD/DD axon guidance defects. Developing growth cones in vivo of fmo-1, fmo-4, fmo-5, and ehbp-1 mutants displayed excessive filopodial protrusion, and transgenic expression of FMO-5 inhibited growth cone protrusion. Mutations suppressed growth cone inhibition caused by activated UNC-40 and UNC-5 signaling, and activated Rac GTPase CED-10 and MIG-2, suggesting that these molecules are required downstream of UNC-6/Netrin receptors and Rac GTPases. From these studies we conclude that FMO-1, FMO-4, FMO-5, and EHBP-1 represent new players downstream of UNC-6/Netrin receptors and Rac GTPases that inhibit growth cone filopodial protrusion in repulsive axon guidance. Mechanisms that guide axons to their targets in the developing nervous system have been elucidated, but how these pathways affect behavior of the growth cone of the axon during outgrowth remains poorly understood. We previously showed that the guidance cue UNC-6/Netrin and its receptors UNC-40/DCC and UNC-5 inhibit lamellipodial and filopodial growth cone protrusion to mediate repulsion from UNC-6/Netrin in C. elegans. Here we report a new mechanism downstream of UNC-6/Netrin involving flavin monooxygenase redox enzymes (FMOs). We show that FMOs are normally required for axon guidance and to inhibit growth cone protrusion. Furthermore, we show that they are required for the anti-protrusive effects of activated UNC-40 and UNC-5 receptors, and that they can partially compensate for loss of molecules in the pathway, indicating that they act downstream of UNC-6/Netrin signaling. Based on the function of the FMO-containing MICAL molecules in Drosophila and vertebrates, we speculate that the FMOs might directly oxidize actin, leading to filament disassembly and collapse, and/or lead to the phosphorylation of UNC-33/CRMP, which we show also genetically interacts with the FMOs downstream of UNC-6/Netrin. In conclusion, this is the first evidence that FMOs might act downstream of UNC-6/Netrin signaling in growth cone protrusion and axon repulsion.
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The Arp2/3 Complex Is Essential for Distinct Stages of Spine Synapse Maturation, Including Synapse Unsilencing. J Neurosci 2017; 36:9696-709. [PMID: 27629719 DOI: 10.1523/jneurosci.0876-16.2016] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 08/02/2016] [Indexed: 12/28/2022] Open
Abstract
UNLABELLED Dendritic filopodia are actin-rich structures that are thought to contribute to early spine synapse formation; however, the actin regulatory proteins important for early synaptogenesis are poorly defined. Using organotypic hippocampal slice cultures and primary neuron hippocampal cultures from Arp2/3 conditional knock-out mice, we analyze the roles of the Arp2/3 complex, an actin regulator that creates branched actin networks, and demonstrate it is essential for distinct stages of both structural and functional maturation of excitatory spine synapses. Our data show that initially the Arp2/3 complex inhibits the formation of dendritic filopodia but that later during development, the Arp2/3 complex drives the morphological maturation from filopodia to typical spine morphology. Furthermore, we demonstrate that although the Arp2/3 complex is not required for key spine maturation steps, such as presynaptic contact and recruitment of MAGUK (membrane-associated guanylate kinase) scaffolding proteins or NMDA receptors, it is necessary for the recruitment of AMPA receptors. This latter process, also known as synapse unsilencing, is a final and essential step in the neurodevelopment of excitatory postsynaptic synaptogenesis, setting the stage for neuronal interconnectivity. These findings provide the first evidence that the Arp2/3 complex is directly involved in functional maturation of dendritic spines during the developmental period of spinogenesis. SIGNIFICANCE STATEMENT Excitatory spine synapse formation (spinogenesis) is a poorly understood yet pivotal period of neurodevelopment that occurs within 2-3 weeks after birth. Neurodevelopmental disorders such as intellectual disability and autism are characterized by abnormal spine structure, which may arise from abnormal excitatory synaptogenesis. The initial stage of spinogenesis is thought to begin with the emergence of actin-rich dendritic filopodia that initiate contact with presynaptic axonal boutons. However, it remains enigmatic how actin cytoskeletal regulation directs dendritic filopodial emergence or their subsequent maturation into dendritic spines during development and on into adulthood. In this study, we provide the first evidence that the Arp2/3 complex, a key actin nucleator, is involved in distinct stages of spine formation and is required for synapse unsilencing.
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Kumar A, Pareek V, Faiq MA, Kumar P, Raza K, Prasoon P, Dantham S, Mochan S. Regulatory role of NGFs in neurocognitive functions. Rev Neurosci 2017; 28:649-673. [DOI: 10.1515/revneuro-2016-0031] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Accepted: 01/25/2017] [Indexed: 12/16/2022]
Abstract
AbstractNerve growth factors (NGFs), especially the prototype NGF and brain-derived neurotrophic factor (BDNF), have a diverse array of functions in the central nervous system through their peculiar set of receptors and intricate signaling. They are implicated not only in the development of the nervous system but also in regulation of neurocognitive functions like learning, memory, synaptic transmission, and plasticity. Evidence even suggests their role in continued neurogenesis and experience-dependent neural network remodeling in adult brain. They have also been associated extensively with brain disorders characterized by neurocognitive dysfunction. In the present article, we aimed to make an exhaustive review of literature to get a comprehensive view on the role of NGFs in neurocognitive functions in health and disease. Starting with historical perspective, distribution in adult brain, implied molecular mechanisms, and developmental basis, this article further provides a detailed account of NGFs’ role in specified neurocognitive functions. Furthermore, it discusses plausible NGF-based homeostatic and adaptation mechanisms operating in the pathogenesis of neurocognitive disorders and has presents a survey of such disorders. Finally, it elaborates on current evidence and future possibilities in therapeutic applications of NGFs with an emphasis on recent research updates in drug delivery mechanisms. Conclusive remarks of the article make a strong case for plausible role of NGFs in comprehensive regulation of the neurocognitive functions and pathogenesis of related disorders and advocate that future research should be directed to explore use of NGF-based mechanisms in the prevention of implicated diseases as well as to target these molecules pharmacologically.
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Affiliation(s)
- Ashutosh Kumar
- Department of Anatomy, All India Institute of Medical Sciences (AIIMS), New Delhi 110029, India
- Department of Anatomy, Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER), Karaikal, Puducherry 609602, India
| | - Vikas Pareek
- Computational Neuroscience and Neuroimaging Division, National Brain Research Centre (NBRC), Manesar, Haryana 122051, India
| | - Muneeb A. Faiq
- Department of Ophthalmology, All India Institute of Medical Sciences (AIIMS), New Delhi 110029, India
| | - Pavan Kumar
- Department of Anatomy, All India Institute of Medical Sciences (AIIMS), New Delhi 110029, India
| | - Khursheed Raza
- Department of Anatomy, All India Institute of Medical Sciences (AIIMS), New Delhi 110029, India
| | - Pranav Prasoon
- Department of Anatomy, All India Institute of Medical Sciences (AIIMS), New Delhi 110029, India
| | - Subrahamanyam Dantham
- Department of Biochemistry, All India Institute of Medical Sciences (AIIMS), New Delhi 110029, India
| | - Sankat Mochan
- Department of Anatomy, All India Institute of Medical Sciences (AIIMS), New Delhi 110029, India
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Hensel N, Claus P. The Actin Cytoskeleton in SMA and ALS: How Does It Contribute to Motoneuron Degeneration? Neuroscientist 2017; 24:54-72. [PMID: 28459188 DOI: 10.1177/1073858417705059] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) and spinal muscular atrophy (SMA) are neurodegenerative diseases with overlapping clinical phenotypes based on impaired motoneuron function. However, the pathomechanisms of both diseases are largely unknown, and it is still unclear whether they converge on the molecular level. SMA is a monogenic disease caused by low levels of functional Survival of Motoneuron (SMN) protein, whereas ALS involves multiple genes as well as environmental factors. Recent evidence argues for involvement of actin regulation as a causative and dysregulated process in both diseases. ALS-causing mutations in the actin-binding protein profilin-1 as well as the ability of the SMN protein to directly bind to profilins argue in favor of a common molecular mechanism involving the actin cytoskeleton. Profilins are major regulat ors of actin-dynamics being involved in multiple neuronal motility and transport processes as well as modulation of synaptic functions that are impaired in models of both motoneuron diseases. In this article, we review the current literature in SMA and ALS research with a focus on the actin cytoskeleton. We propose a common molecular mechanism that explains the degeneration of motoneurons for SMA and some cases of ALS.
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Affiliation(s)
- Niko Hensel
- 1 Institute of Neuroanatomy and Cell Biology, Hannover Medical School, Hannover, Germany.,2 Niedersachsen Network on Neuroinfectiology (N-RENNT), Hannover, Germany
| | - Peter Claus
- 1 Institute of Neuroanatomy and Cell Biology, Hannover Medical School, Hannover, Germany.,2 Niedersachsen Network on Neuroinfectiology (N-RENNT), Hannover, Germany.,3 Center for Systems Neuroscience (ZSN), Hannover, Germany
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Kim HJ, Choi HS, Park JH, Kim MJ, Lee HG, Petersen RB, Kim YS, Park JB, Choi EK. Regulation of RhoA activity by the cellular prion protein. Cell Death Dis 2017; 8:e2668. [PMID: 28300846 PMCID: PMC5386549 DOI: 10.1038/cddis.2017.37] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Revised: 12/18/2016] [Accepted: 01/10/2017] [Indexed: 01/28/2023]
Abstract
The cellular prion protein (PrPC) is a highly conserved glycosylphosphatidylinositol (GPI)-anchored membrane protein that is involved in the signal transduction during the initial phase of neurite outgrowth. The Ras homolog gene family member A (RhoA) is a small GTPase that is known to have an essential role in regulating the development, differentiation, survival, and death of neurons in the central nervous system. Although recent studies have shown the dysregulation of RhoA in a variety of neurodegenerative diseases, the role of RhoA in prion pathogenesis remains unclear. Here, we investigated the regulation of RhoA-mediated signaling by PrPC using both in vitro and in vivo models and found that overexpression of PrPC significantly induced RhoA inactivation and RhoA phosphorylation in hippocampal neuronal cells and in the brains of transgenic mice. Using siRNA-mediated depletion of endogenous PrPC and overexpression of disease-associated mutants of PrPC, we confirmed that PrPC induced RhoA inactivation, which accompanied RhoA phosphorylation but reduced the phosphorylation levels of LIM kinase (LIMK), leading to cofilin activation. In addition, PrPC colocalized with RhoA, and the overexpression of PrPC significantly increased neurite outgrowth in nerve growth factor-treated PC12 cells through RhoA inactivation. However, the disease-associated mutants of PrPC decreased neurite outgrowth compared with wild-type PrPC. Moreover, inhibition of Rho-associated kinase (ROCK) substantially facilitated neurite outgrowth in NGF-treated PC12 cells, similar to the effect induced by PrPC. Interestingly, we found that the induction of RhoA inactivation occurred through the interaction of PrPC with RhoA and that PrPC enhanced the interaction between RhoA and p190RhoGAP (a GTPase-activating protein). These findings suggest that the interactions of PrPC with RhoA and p190RhoGAP contribute to neurite outgrowth by controlling RhoA inactivation and RhoA-mediated signaling and that disease-associated mutations of PrPC impair RhoA inactivation, which in turn leads to prion-related neurodegeneration.
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Affiliation(s)
- Hee-Jun Kim
- Ilsong Institute of Life Science, Hallym University, Anyang, Republic of Korea
| | - Hong-Seok Choi
- Ilsong Institute of Life Science, Hallym University, Anyang, Republic of Korea.,Department of Microbiology, College of Medicine, Hallym University, Chuncheon, Republic of Korea
| | - Jeong-Ho Park
- Ilsong Institute of Life Science, Hallym University, Anyang, Republic of Korea.,Department of Microbiology, College of Medicine, Hallym University, Chuncheon, Republic of Korea
| | - Mo-Jong Kim
- Ilsong Institute of Life Science, Hallym University, Anyang, Republic of Korea.,Department of Biomedical Gerontology, Graduate School of Hallym University, Chuncheon, Republic of Korea
| | - Hyoung-Gon Lee
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX, USA
| | - Robert Bob Petersen
- Department of Pathology, Case Western Reserve University, Cleveland, OH, USA.,Departments of Neuroscience and Neurology, Case Western Reserve University, Cleveland, OH, USA
| | - Yong-Sun Kim
- Ilsong Institute of Life Science, Hallym University, Anyang, Republic of Korea.,Department of Microbiology, College of Medicine, Hallym University, Chuncheon, Republic of Korea
| | - Jae-Bong Park
- Department of Biochemistry, College of Medicine, Hallym University, Chuncheon, Republic of Korea
| | - Eun-Kyoung Choi
- Ilsong Institute of Life Science, Hallym University, Anyang, Republic of Korea.,Department of Biomedical Gerontology, Graduate School of Hallym University, Chuncheon, Republic of Korea
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Iseppon F, Napolitano LM, Torre V, Cojoc D. Combining FRET and optical tweezers to study RhoGTPases spatio-temporal dynamics upon local stimulation. J Biol Methods 2017; 4:e65. [PMID: 31453225 PMCID: PMC6708921 DOI: 10.14440/jbm.2017.159] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Revised: 01/02/2017] [Accepted: 01/25/2017] [Indexed: 01/26/2023] Open
Abstract
Local stimulation with optical tweezers has been used to mimic natural stimuli that occur in biological processes such as cell migration or differentiation. Carriers (beads and lipid vesicles) with sizes down to 30 nm can be manipulated with a high spatial and temporal resolution: they are positioned with a sub-micrometric precision on a specific cell compartment and the beginning of the stimulation can be triggered with millisecond precision. RhoGTPases are a Ras-related family of proteins that regulate many different functions including cell polarity, microtubule dynamics and membrane transport pathways. Here we combine local stimulation with FRET microscopy to study RhoGTPases spatial and temporal activation following guidance cue local stimulation. We used two different vectors for local delivery: silica micro-beads and micro-sized lipid vesicles. The experimental methods associated with neuronal growth cone local stimulation are discussed in detail, as well as the analysis methods. Here we present a protocol that enables to study neuronal growth cone cytoskeleton rearrangements in response to a gradient of molecules in a way that better mimics physiological conditions, and it can be similarly applied to each secreted molecule involved in cell signaling.
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Affiliation(s)
- Federico Iseppon
- Neuroscience Area, International School for Advanced Studies, Trieste, Italy
| | - Luisa Mr Napolitano
- Neuroscience Area, International School for Advanced Studies, Trieste, Italy
| | - Vincent Torre
- Neuroscience Area, International School for Advanced Studies, Trieste, Italy
| | - Dan Cojoc
- Optical Manipulation Lab, CNR-IOM, the National Research Council of Italy - Institute of Materials, Trieste, Italy
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36
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Tanouchi A, Taniuchi K, Furihata M, Naganuma S, Dabanaka K, Kimura M, Watanabe R, Kohsaki T, Shimizu T, Saito M, Hanazaki K, Saibara T. CCDC88A, a prognostic factor for human pancreatic cancers, promotes the motility and invasiveness of pancreatic cancer cells. JOURNAL OF EXPERIMENTAL & CLINICAL CANCER RESEARCH : CR 2016; 35:190. [PMID: 27919290 PMCID: PMC5139074 DOI: 10.1186/s13046-016-0466-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Accepted: 11/24/2016] [Indexed: 12/21/2022]
Abstract
BACKGROUND Coiled-Coil Domain Containing 88A (CCDC88A) was identified as a substrate of the serine/threonine kinase Akt that is capable of binding to the actin cytoskeleton. The aim of this study was to investigate the potential role of CCDC88A in the migration and invasiveness of pancreatic ductal adenocarcinoma (PDAC) cells. METHODS Immunohistochemistry was performed to determine whether high CCDC88A expression in human PDAC tissues is correlated with poor prognosis. Immunoprecipitation, immunoblotting and immunocytochemistry were performed to determine the intracellular distribution of CCDC88A, and its association with the serine/threonine kinase Akt and actin-filaments in PDAC cells. Phosphoprotein array analysis was performed to determine CCDC88A-associated intracellular signaling pathways. Finally, immunofluorescence analyses and Matrigel invasion assays were performed to examine the effects of CCDC88A on the formation of cell protrusions and PDAC cell invasion. RESULTS Expression of CCDC88A in PDAC tissue was significantly correlated with overall survival. CCDC88A was co-localized with peripheral actin structures in cell protrusions of migrating PDAC cells. Knockdown of CCDC88A inhibited the migration and invasiveness of PDAC cells through a decrease in cell protrusions. Although CCDC88A has been previously reported to be a binding partner and substrate of Akt, the level of active Akt was not associated with the translocation of CCDC88A towards cell protrusions. CCDC88A-dependent promotion of cell migration and invasiveness was not modulated by Akt signaling. Knockdown of CCDC88A decreased phosphorylated Src and ERK1/2 and increased phosphorylated AMPK1 in PDAC cells. Knockdown of AMPK1 inhibited the migration and invasiveness of PDAC cells. The combined data suggest that CCDC88A may be a useful marker for predicting the outcome of patients with PDAC and that CCDC88A can promote PDAC cell migration and invasion through a signaling pathway that involves phosphorylation of Src and ERK1/2 and/or dephosphorylation of AMPK1. CONCLUSIONS CCDC88A was accumulated in cell protrusions, contributed to the formation of membrane protrusions, and increased the migration and invasiveness of PDAC cells.
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Affiliation(s)
- Aki Tanouchi
- Department of Gastroenterology and Hepatology; Kochi Medical School, Kochi University, Kochi, Japan.
| | - Keisuke Taniuchi
- Department of Gastroenterology and Hepatology; Kochi Medical School, Kochi University, Kochi, Japan.,Departments of Endoscopic Diagnostics and Therapeutics, Kochi Medical School, Kochi University, Kohasu, Oko-cho, Nankoku, Kochi, 783-8505, Japan
| | - Mutsuo Furihata
- Department of Pathology, Kochi Medical School, Kochi University, Kochi, Japan
| | - Seiji Naganuma
- Department of Pathology, Kochi Medical School, Kochi University, Kochi, Japan
| | - Ken Dabanaka
- Department of Surgery, Kochi Medical School, Kochi University, Kochi, Japan
| | - Masashi Kimura
- Department of Surgery, Matsuyama Shimin Hospital, Matsuyama, Japan
| | - Ryohei Watanabe
- Department of Surgery, Matsuyama Shimin Hospital, Matsuyama, Japan
| | - Takuhiro Kohsaki
- Department of Gastroenterology and Hepatology; Kochi Medical School, Kochi University, Kochi, Japan
| | - Takahiro Shimizu
- Department of Pharmacology, Kochi Medical School, Kochi University, Kochi, Japan
| | - Motoaki Saito
- Department of Pharmacology, Kochi Medical School, Kochi University, Kochi, Japan
| | - Kazuhiro Hanazaki
- Department of Surgery, Kochi Medical School, Kochi University, Kochi, Japan
| | - Toshiji Saibara
- Department of Gastroenterology and Hepatology; Kochi Medical School, Kochi University, Kochi, Japan.,Departments of Endoscopic Diagnostics and Therapeutics, Kochi Medical School, Kochi University, Kohasu, Oko-cho, Nankoku, Kochi, 783-8505, Japan
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37
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Raza Q, Jacobs JR. Guidance signalling regulates leading edge behaviour during collective cell migration of cardiac cells in Drosophila. Dev Biol 2016; 419:285-297. [PMID: 27618756 DOI: 10.1016/j.ydbio.2016.09.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Revised: 09/04/2016] [Accepted: 09/05/2016] [Indexed: 01/31/2023]
Abstract
Collective cell migration is the coordinated movement of cells, which organize tissues during morphogenesis, repair and some cancers. The motile cell membrane of the advancing front in collective cell migration is termed the Leading Edge. The embryonic development of the vertebrate and Drosophila hearts are both characterized by the coordinated medial migration of a bilateral cluster of mesodermal cells. In Drosophila, the cardioblasts form cohesive bilateral rows that migrate collectively as a unit towards the dorsal midline to form the dorsal vessel. We have characterized the collective cell migration of cardioblasts as an in vivo quantitative model to study the behaviour of the Leading Edge. We investigated whether guidance signalling through Slit and Netrin pathways plays a role in cell migration during heart development. Through time-lapse imaging and quantitative assessment of migratory behaviour of the cardioblasts in loss-of-function mutants, we demonstrate that both Slit and Netrin mediated signals are autonomously and concomitantly required to maximize migration velocity, filopodial and lamellipodial activities. Additionally, we show that another Slit and Netrin receptor, Dscam1, the role of which during heart development was previously unknown, is required for both normal migration of cardioblasts and luminal expansion. Leading edge behaviour analysis revealed a dosage dependent genetic interaction between Slit and Netrin receptors suggesting that downstream signalling through these receptors converge on a common output that increases leading edge activity of the cardioblasts. Finally, we found that guidance signalling maintains the balance between epithelial and mesenchymal characteristics of the migrating cardioblasts.
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Affiliation(s)
- Qanber Raza
- Department of Biology, McMaster University, 1280 Main St W, Hamilton, ON, Canada L8S 4L8
| | - J Roger Jacobs
- Department of Biology, McMaster University, 1280 Main St W, Hamilton, ON, Canada L8S 4L8.
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38
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Naoki H, Nishiyama M, Togashi K, Igarashi Y, Hong K, Ishii S. Multi-phasic bi-directional chemotactic responses of the growth cone. Sci Rep 2016; 6:36256. [PMID: 27808115 PMCID: PMC5093620 DOI: 10.1038/srep36256] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2015] [Accepted: 10/12/2016] [Indexed: 11/23/2022] Open
Abstract
The nerve growth cone is bi-directionally attracted and repelled by the same cue molecules depending on the situations, while other non-neural chemotactic cells usually show uni-directional attraction or repulsion toward their specific cue molecules. However, how the growth cone differs from other non-neural cells remains unclear. Toward this question, we developed a theory for describing chemotactic response based on a mathematical model of intracellular signaling of activator and inhibitor. Our theory was first able to clarify the conditions of attraction and repulsion, which are determined by balance between activator and inhibitor, and the conditions of uni- and bi-directional responses, which are determined by dose-response profiles of activator and inhibitor to the guidance cue. With biologically realistic sigmoidal dose-responses, our model predicted tri-phasic turning response depending on intracellular Ca2+ level, which was then experimentally confirmed by growth cone turning assays and Ca2+ imaging. Furthermore, we took a reverse-engineering analysis to identify balanced regulation between CaMKII (activator) and PP1 (inhibitor) and then the model performance was validated by reproducing turning assays with inhibitions of CaMKII and PP1. Thus, our study implies that the balance between activator and inhibitor underlies the multi-phasic bi-directional turning response of the growth cone.
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Affiliation(s)
- Honda Naoki
- Graduate School of Medicine, Kyoto University, Sakyo, Kyoto, Japan.,Imaging Platform for Spatio-temporal Information, Kyoto University, Sakyo, Kyoto, Japan
| | - Makoto Nishiyama
- Department of Biochemistry, New York University School of Medicine, New York, USA.,Kasah Technology Inc. New York, New York, USA
| | - Kazunobu Togashi
- Department of Biochemistry, New York University School of Medicine, New York, USA
| | | | - Kyonsoo Hong
- Department of Biochemistry, New York University School of Medicine, New York, USA.,Kasah Technology Inc. New York, New York, USA
| | - Shin Ishii
- Imaging Platform for Spatio-temporal Information, Kyoto University, Sakyo, Kyoto, Japan.,Graduate School of Informatics, Kyoto University, Sakyo, Kyoto, Japan
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Using Rotary Shadow Electron Microscopy to Characterize Semaphorin-Mediated Growth Cone Collapse. Methods Mol Biol 2016. [PMID: 27787851 DOI: 10.1007/978-1-4939-6448-2_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Rotary shadow electron microscopy (EM) of growth cone cytoskeletons provides a high-resolution method for detecting both global and macromolecular changes in cytoskeletal organization or structure. This approach can be used to study responses to repulsive guidance factors such as semaphorin 3A. Here I describe the procedures used to prepare cultured neurons for rotary-shadow EM, allowing detailed comparisons of cytoskeletal structure.
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40
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Morales D, Kania A. Cooperation and crosstalk in axon guidance cue integration: Additivity, synergy, and fine-tuning in combinatorial signaling. Dev Neurobiol 2016; 77:891-904. [PMID: 27739221 DOI: 10.1002/dneu.22463] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 08/17/2016] [Accepted: 10/10/2016] [Indexed: 12/31/2022]
Abstract
Neural circuit development involves the coordinated growth and guidance of axons to their targets. Following the identification of many guidance cue molecules, recent experiments have focused on the interactions of their signaling cascades, which can be generally classified as additive or non-additive depending on the signal convergence point. While additive (parallel) signaling suggests limited molecular interaction between the pathways, non-additive signaling involves crosstalk between pathways and includes more complex synergistic, hierarchical, and permissive guidance cue relationships. Here the authors have attempted to classify recent studies that describe axon guidance signal integration according to these divisions. They also discuss the mechanistic implications of such interactions, as well as general ideas relating signal integration to the generation of diversity of axon guidance responses. © 2016 Wiley Periodicals, Inc. Develop Neurobiol 77: 891-904, 2017.
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Affiliation(s)
- Daniel Morales
- Institut de recherches cliniques de Montréal (IRCM), Montréal, Quebec, H2W 1R7, Canada.,Integrated Program in Neuroscience, McGill University, Montréal, Quebec, H3A 2B4, Canada
| | - Artur Kania
- Institut de recherches cliniques de Montréal (IRCM), Montréal, Quebec, H2W 1R7, Canada.,Integrated Program in Neuroscience, McGill University, Montréal, Quebec, H3A 2B4, Canada.,Department of Anatomy and Cell Biology, Division of Experimental Medicine, McGill University, Montréal, Quebec, H3A 2B2, Canada.,Department of Biology, Division of Experimental Medicine, McGill University, Montréal, Quebec, H3A 2B2, Canada.,Faculté de Médecine, Université de Montréal, Montréal, Quebec, H3C 3J7, Canada
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41
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Jiang X, Lachance M, Rossignol E. Involvement of cortical fast-spiking parvalbumin-positive basket cells in epilepsy. PROGRESS IN BRAIN RESEARCH 2016; 226:81-126. [PMID: 27323940 DOI: 10.1016/bs.pbr.2016.04.012] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
GABAergic interneurons of the parvalbumin-positive fast-spiking basket cells subtype (PV INs) are important regulators of cortical network excitability and of gamma oscillations, involved in signal processing and cognition. Impaired development or function of PV INs has been associated with epilepsy in various animal models of epilepsy, as well as in some genetic forms of epilepsy in humans. In this review, we provide an overview of some of the experimental data linking PV INs dysfunction with epilepsy, focusing on disorders of the specification, migration, maturation, synaptic function, or connectivity of PV INs. Furthermore, we reflect on the potential therapeutic use of cell-type specific stimulation of PV INs within active networks and on the transplantation of PV INs precursors in the treatment of epilepsy and its comorbidities.
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Affiliation(s)
- X Jiang
- Université de Montréal, Montréal, QC, Canada; CHU Ste-Justine Research Center, Montréal, QC, Canada
| | - M Lachance
- CHU Ste-Justine Research Center, Montréal, QC, Canada
| | - E Rossignol
- Université de Montréal, Montréal, QC, Canada; CHU Ste-Justine Research Center, Montréal, QC, Canada.
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42
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McConnell RE, Edward van Veen J, Vidaki M, Kwiatkowski AV, Meyer AS, Gertler FB. A requirement for filopodia extension toward Slit during Robo-mediated axon repulsion. J Cell Biol 2016; 213:261-74. [PMID: 27091449 PMCID: PMC5084274 DOI: 10.1083/jcb.201509062] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Accepted: 03/04/2016] [Indexed: 12/11/2022] Open
Abstract
Axons navigate long distances through complex 3D environments to interconnect the nervous system during development. Although the precise spatiotemporal effects of most axon guidance cues remain poorly characterized, a prevailing model posits that attractive guidance cues stimulate actin polymerization in neuronal growth cones whereas repulsive cues induce actin disassembly. Contrary to this model, we find that the repulsive guidance cue Slit stimulates the formation and elongation of actin-based filopodia from mouse dorsal root ganglion growth cones. Surprisingly, filopodia form and elongate toward sources of Slit, a response that we find is required for subsequent axonal repulsion away from Slit. Mechanistically, Slit evokes changes in filopodium dynamics by increasing direct binding of its receptor, Robo, to members of the actin-regulatory Ena/VASP family. Perturbing filopodium dynamics pharmacologically or genetically disrupts Slit-mediated repulsion and produces severe axon guidance defects in vivo. Thus, Slit locally stimulates directional filopodial extension, a process that is required for subsequent axonal repulsion downstream of the Robo receptor.
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Affiliation(s)
- Russell E McConnell
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 01239
| | - J Edward van Veen
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 01239 Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 01239
| | - Marina Vidaki
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 01239
| | - Adam V Kwiatkowski
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 01239
| | - Aaron S Meyer
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 01239 Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 01239
| | - Frank B Gertler
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 01239 Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 01239
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43
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The pruritus- and TH2-associated cytokine IL-31 promotes growth of sensory nerves. J Allergy Clin Immunol 2016; 138:500-508.e24. [PMID: 27212086 DOI: 10.1016/j.jaci.2016.02.020] [Citation(s) in RCA: 174] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Revised: 01/25/2016] [Accepted: 02/04/2016] [Indexed: 01/27/2023]
Abstract
BACKGROUND Pruritus is a cardinal symptom of atopic dermatitis, and an increased cutaneous sensory network is thought to contribute to pruritus. Although the immune cell-IL-31-neuron axis has been implicated in severe pruritus during atopic skin inflammation, IL-31's neuropoietic potential remains elusive. OBJECTIVE We sought to analyze the IL-31-related transcriptome in sensory neurons and to investigate whether IL-31 promotes sensory nerve fiber outgrowth. METHODS In vitro primary sensory neuron culture systems were subjected to whole-transcriptome sequencing, ingenuity pathway analysis, immunofluorescence, and nerve elongation, as well as branching assays after IL-31 stimulation. In vivo we investigated the cutaneous sensory neuronal network in wild-type, Il31-transgenic, and IL-31 pump-equipped mice. RESULTS Transgenic Il31 overexpression and subcutaneously delivered IL-31 induced an increase in the cutaneous nerve fiber density in lesional skin in vivo. Transcriptional profiling of IL-31-activated dorsal root ganglia neurons revealed enrichment for genes promoting nervous system development and neuronal outgrowth and negatively regulating cell death. Moreover, the growth cones of primary small-diameter dorsal root ganglia neurons showed abundant IL-31 receptor α expression. Indeed, IL-31 selectively promoted nerve fiber extension only in small-diameter neurons. Signal transducer and activator of transcription 3 phosphorylation mediated IL-31-induced neuronal outgrowth, and pharmacologic inhibition of signal transducer and activator of transcription 3 completely abolished this effect. In contrast, transient receptor potential cation channel vanilloid subtype 1 channels were dispensable for IL-31-induced neuronal sprouting. CONCLUSIONS The pruritus- and TH2-associated novel cytokine IL-31 induces a distinct transcriptional program in sensory neurons, leading to nerve elongation and branching both in vitro and in vivo. This finding might help us understand the clinical observation that patients with atopic dermatitis experience increased sensitivity to minimal stimuli inducing sustained itch.
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44
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Alvarez Juliá A, Frasch AC, Fuchsova B. Neuronal filopodium formation induced by the membrane glycoprotein M6a (Gpm6a) is facilitated by coronin-1a, Rac1, and p21-activated kinase 1 (Pak1). J Neurochem 2016; 137:46-61. [PMID: 26809475 DOI: 10.1111/jnc.13552] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Revised: 01/18/2016] [Accepted: 01/19/2016] [Indexed: 01/01/2023]
Abstract
Stress-responsive neuronal membrane glycoprotein M6a (Gpm6a) functions in neurite extension, filopodium and spine formation and synaptogenesis. The mechanisms of Gpm6a action in these processes are incompletely understood. Previously, we identified the actin regulator coronin-1a (Coro1a) as a putative Gpm6a interacting partner. Here, we used co-immunoprecipitation assays with the anti-Coro1a antibody to show that Coro1a associates with Gpm6a in rat hippocampal neurons. By immunofluorescence microscopy, we demonstrated that in hippocampal neurons Coro1a localizes in F-actin-enriched regions and some of Coro1a spots co-localize with Gpm6a labeling. Notably, the over-expression of a dominant-negative form of Coro1a as well as its down-regulation by siRNA interfered with Gpm6a-induced filopodium formation. Coro1a is known to regulate the plasma membrane translocation and activation of small GTPase Rac1. We show that Coro1a co-immunoprecipitates with Rac1 together with Gpm6a. Pharmacological inhibition of Rac1 resulted in a significant decrease in filopodium formation by Gpm6a. The same was observed upon the co-expression of Gpm6a with the inactive GDP-bound form of Rac1. In this case, the elevated membrane recruitment of GDP-bound Rac1 was detected as well. Moreover, the kinase activity of the p21-activated kinase 1 (Pak1), a main downstream effector of Rac1 that acts downstream of Coro1a, was required for Gpm6a-induced filopodium formation. Taken together, our results provide evidence that a signaling pathway including Coro1a, Rac1, and Pak1 facilitates Gpm6a-induced filopodium formation. Formation of filopodia by membrane glycoprotein M6a (Gpm6a) requires actin regulator coronin-1a (Coro1a), known to regulate plasma membrane localization and activation of Rac1 and its downstream effector Pak1. Coro1a associates with Gpm6a. Blockage of Coro1a, Rac1, or Pak1 interferes with Gpm6a-induced filopodium formation. Moreover, Gpm6a facilitates Rac1 membrane recruitment. Altogether, a mechanistic insight into the process of Gpm6a-induced neuronal filopodium formation is provided.
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Affiliation(s)
- Anabel Alvarez Juliá
- Instituto de Investigaciones Biotecnológicas IIB-INTECH, CONICET-UNSAM, San Martin, Argentina
| | - Alberto C Frasch
- Instituto de Investigaciones Biotecnológicas IIB-INTECH, CONICET-UNSAM, San Martin, Argentina
| | - Beata Fuchsova
- Instituto de Investigaciones Biotecnológicas IIB-INTECH, CONICET-UNSAM, San Martin, Argentina
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45
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Charcot-Marie-Tooth 2b associated Rab7 mutations cause axon growth and guidance defects during vertebrate sensory neuron development. Neural Dev 2016; 11:2. [PMID: 26791407 PMCID: PMC4721196 DOI: 10.1186/s13064-016-0058-x] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Accepted: 01/11/2016] [Indexed: 12/02/2022] Open
Abstract
Background Charcot-Marie-Tooth2b (CMT2b) is an axonal form of a human neurodegenerative disease that preferentially affects sensory neurons. CMT2b is dominantly inherited and is characterized by unusually early onset, presenting in the second or third decade of life. Five missense mutations in the gene encoding Rab7 GTPase have been identified as causative in human CMT2b disease. Although several studies have modeled CMT2b disease in cultured neurons and in Drosophila, the mechanisms by which defective Rab7 leads to disease remain poorly understood. Results We used zebrafish to investigate the effects of CMT2b-associated Rab7 mutations in a vertebrate model. We generated transgenic animals expressing the CMT2b-associated mutant forms of Rab7 in sensory neurons, and show that these Rab7 variants cause neurodevelopmental defects, including defects in sensory axon growth, branching and pathfinding at early developmental stages. We also find reduced axon growth and branching in neurons expressing a constitutively active form of Rab7, suggesting these defects may be caused by Rab7 gain-of-function. Further, we use high-speed, high-resolution imaging of endosome transport in vivo and find that CMT2b-associated Rab7 variants cause reduced vesicle speeds, suggesting altered transport may underlie axon development defects. Conclusions Our data provide new insight into how disease-associated alterations in Rab7 protein disrupt cellular function in vertebrate sensory neurons. Moreover, our findings suggest that defects in axon development may be a previously unrecognized component of CMT2b disease.
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46
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Lehtimäki J, Hakala M, Lappalainen P. Actin Filament Structures in Migrating Cells. Handb Exp Pharmacol 2016; 235:123-152. [PMID: 27469496 DOI: 10.1007/164_2016_28] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Cell migration is necessary for several developmental processes in multicellular organisms. Furthermore, many physiological processes such as wound healing and immunological events in adult animals are dependent on cell migration. Consequently, defects in cell migration are linked to various diseases including immunological disorders as well as cancer progression and metastasis formation. Cell migration is driven by specific protrusive and contractile actin filament structures, but the types and relative contributions of these actin filament arrays vary depending on the cell type and the environment of the cell. In this chapter, we introduce the most important actin filament structures that contribute to mesenchymal and amoeboid cell migration modes and discuss the mechanisms by which the assembly and turnover of these structures are controlled by various actin-binding proteins.
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Affiliation(s)
- Jaakko Lehtimäki
- Institute of Biotechnology, University of Helsinki, 56, 00014, Helsinki, Finland
| | - Markku Hakala
- Institute of Biotechnology, University of Helsinki, 56, 00014, Helsinki, Finland
| | - Pekka Lappalainen
- Institute of Biotechnology, University of Helsinki, 56, 00014, Helsinki, Finland.
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47
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Kilinc D, Schwab J, Rampini S, Ikpekha OW, Thampi A, Blasiak A, Li P, Schwamborn R, Kolch W, Matallanas D, Lee GU. A microfluidic dual gradient generator for conducting cell-based drug combination assays. Integr Biol (Camb) 2016; 8:39-49. [DOI: 10.1039/c5ib00209e] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
We present a microfluidic gradient generator that exposes cultured cells to orthogonally-aligned linear concentration gradients of two molecules. Live-cell assays quantifying apoptotic signaling and cell motility are provided as proof-of-concept.
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Affiliation(s)
- Devrim Kilinc
- School of Chemistry and Chemical Biology
- University College Dublin
- Dublin 4
- Ireland
- UCD Conway Institute
| | - Jefrem Schwab
- School of Chemistry and Chemical Biology
- University College Dublin
- Dublin 4
- Ireland
| | - Stefano Rampini
- School of Chemistry and Chemical Biology
- University College Dublin
- Dublin 4
- Ireland
| | - Oshoke W. Ikpekha
- School of Chemistry and Chemical Biology
- University College Dublin
- Dublin 4
- Ireland
| | - Ashwin Thampi
- School of Chemistry and Chemical Biology
- University College Dublin
- Dublin 4
- Ireland
| | - Agata Blasiak
- School of Chemistry and Chemical Biology
- University College Dublin
- Dublin 4
- Ireland
| | - Peng Li
- School of Chemistry and Chemical Biology
- University College Dublin
- Dublin 4
- Ireland
| | | | - Walter Kolch
- UCD Conway Institute
- Dublin 4
- Ireland
- Systems Biology Ireland
- UCD
| | | | - Gil U. Lee
- School of Chemistry and Chemical Biology
- University College Dublin
- Dublin 4
- Ireland
- UCD Conway Institute
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48
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Özel MN, Langen M, Hassan BA, Hiesinger PR. Filopodial dynamics and growth cone stabilization in Drosophila visual circuit development. eLife 2015; 4. [PMID: 26512889 PMCID: PMC4728134 DOI: 10.7554/elife.10721] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Accepted: 10/26/2015] [Indexed: 01/04/2023] Open
Abstract
Filopodial dynamics are thought to control growth cone guidance, but the types and roles of growth cone dynamics underlying neural circuit assembly in a living brain are largely unknown. To address this issue, we have developed long-term, continuous, fast and high-resolution imaging of growth cone dynamics from axon growth to synapse formation in cultured Drosophila brains. Using R7 photoreceptor neurons as a model we show that >90% of the growth cone filopodia exhibit fast, stochastic dynamics that persist despite ongoing stepwise layer formation. Correspondingly, R7 growth cones stabilize early and change their final position by passive dislocation. N-Cadherin controls both fast filopodial dynamics and growth cone stabilization. Surprisingly, loss of N-Cadherin causes no primary targeting defects, but destabilizes R7 growth cones to jump between correct and incorrect layers. Hence, growth cone dynamics can influence wiring specificity without a direct role in target recognition and implement simple rules during circuit assembly. DOI:http://dx.doi.org/10.7554/eLife.10721.001 Genes encode complicated developmental processes, but it is clear that genetic information cannot encode each and every individual connection that forms between the nerve cells in a brain. Instead, the individual cells and nerve endings must make decisions during brain development. Up until now, few examples were known for how these nerve endings move and choose their paths and partners in a living, developing brain. The fruit fly Drosophila provides a useful model to explore the ‘wiring’ of nerve cells in the brain, partly because a fruit fly’s brain develops within a few days. However, most previous studies have relied on identifying mutant flies with disrupted brain wiring and studying them using still images. Now, Özel et al. have developed a new imaging method that has enough resolution and speed over sufficiently long periods to track the growing nerve endings in a developing fly brain. The method was applied to a model nerve cell in the fly’s visual system. This revealed that most of this nerve’s dynamic changes are short-lived and random, and appear to help to stabilize the developing nerve ending, rather than guide it to a target. Özel et al. also found that a protein called N-Cadherin, previously thought to be required for the targeting of developing nerve endings, actually plays a role in their stabilization. These findings uncover the roles of changes in nerve endings during long-term brain development; this was previously largely unknown for any organism. The next stage in this research will involve further analyses of both wild type and mutant flies to try and work out general principles about how the brain develops via the decoding of genetic information. DOI:http://dx.doi.org/10.7554/eLife.10721.002
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Affiliation(s)
- Mehmet Neset Özel
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, United States.,Division of Neurobiology, Institute for Biology, Freie Universität Berlin, Berlin, Germany.,NeuroCure Cluster of Excellence, Charite Universitätsmedizin Berlin, Berlin, Germany
| | - Marion Langen
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, United States
| | - Bassem A Hassan
- Center for the Biology of Disease, Vlaams Instituut voor Biotechnologie, Leuven, Belgium.,Center for Human Genetics, University of Leuven School of Medicine, Leuven, Belgium
| | - P Robin Hiesinger
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, United States.,Division of Neurobiology, Institute for Biology, Freie Universität Berlin, Berlin, Germany.,NeuroCure Cluster of Excellence, Charite Universitätsmedizin Berlin, Berlin, Germany
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49
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Gillon A, Sheard P. Elderly mouse skeletal muscle fibres have a diminished capacity to upregulate NCAM production in response to denervation. Biogerontology 2015; 16:811-23. [PMID: 26385499 DOI: 10.1007/s10522-015-9608-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Accepted: 09/14/2015] [Indexed: 01/17/2023]
Abstract
Sarcopenia is a major contributor to the loss of independence and deteriorating quality of life in elderly individuals, it manifests as a decline in skeletal muscle mass and strength beyond the age of 65. Muscle fibre atrophy is a major contributor to sarcopenia and the most severely atrophic fibres are commonly found in elderly muscles to have permanently lost their motor nerve input. By contrast with elderly fibres, when fibres in young animals lose their motor input they normally mount a response to induce restoration of nerve contact, and this is mediated in part by upregulated expression of the nerve cell adhesion molecule (NCAM). Therefore, skeletal muscles appear to progressively lose their ability to become reinnervated, and here we have investigated whether this decline occurs via loss of the muscle's ability to upregulate NCAM in response to denervation. We performed partial denervation (by peripheral nerve crush) of the extensor digitorum longus muscle of the lower limb in both young and elderly mice. We used immunohistochemistry to compare relative NCAM levels at denervated and control innervated muscle fibres, focused on measurements at neuromuscular junctional, extra-junctional and cytoplasmic locations. Muscle fibres in young animals responded to denervation with significant (32.9%) increases in unpolysialylated NCAM at extra-junctional locations, but with no change in polysialylated NCAM. The same partial denervation protocol applied to elderly animals resulted in no significant change in either polysialylated or unpolysialylated NCAM at junctional, extra-junctional or cytoplasmic locations, therefore muscle fibres in young mice upregulated NCAM in response to denervation but fibres in elderly mice failed to do so. Elevation of NCAM levels is likely to be an important component of the muscle fibre's ability to attract or reattract a neural input, so we conclude that the presence of increasing numbers of long-term denervated fibres in elderly muscles is due, at least in part, to the fibre's declining ability to mount a normal response to loss of motor input.
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Affiliation(s)
- Ashley Gillon
- Department of Physiology, Otago School of Medical Sciences, University of Otago, P.O. Box 913, Dunedin, New Zealand.
| | - Philip Sheard
- Department of Physiology, Otago School of Medical Sciences, University of Otago, P.O. Box 913, Dunedin, New Zealand.
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50
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Kim DH, Moon EY, Yi JH, Lee HE, Park SJ, Ryu YK, Kim HC, Lee S, Ryu JH. Peptide fragment of thymosin β4 increases hippocampal neurogenesis and facilitates spatial memory. Neuroscience 2015; 310:51-62. [PMID: 26363149 DOI: 10.1016/j.neuroscience.2015.09.017] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Revised: 09/01/2015] [Accepted: 09/01/2015] [Indexed: 12/16/2022]
Abstract
Although several studies have suggested the neuroprotective effect of thymosin β4 (TB4), a major actin-sequestering protein, on the central nervous system, little is understood regarding the action of N-acetyl-serylaspartyl-lysyl-proline (Ac-SDKP), a peptide fragment of TB4 on brain function. Here, we examined neurogenesis-stimulative effect of Ac-SDKP. Intrahippocampal infusion of Ac-SDKP facilitated the generation of new neurons in the hippocampus. Ac-SDKP-treated mouse hippocampus showed an increase in β-catenin stability with reduction of glycogen synthase kinase-3β (GSK-3β) activity. Moreover, inhibition of vascular endothelial growth factor (VEGF) signaling blocked Ac-SDKP-facilitated neural proliferation. Subchronic intrahippocampal infusion of Ac-SDKP also increased spatial memory. Taken together, these data demonstrate that Ac-SDKP functions as a regulator of neural proliferation and indicate that Ac-SDKP may be a therapeutic candidate for diseases characterized by neuronal loss.
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Affiliation(s)
- D H Kim
- Department of Medicinal Biotechnology, College of Natural Resources and Life Science, Dong-A University, Busan 604-714, Republic of Korea; Dong-A Anti-Aging Research Center, Dong-A University, Busan 604-714, Republic of Korea
| | - E-Y Moon
- Department of Bioscience and Biotechnology, Sejong University, Seoul 143-747, Republic of Korea.
| | - J H Yi
- School of Clinical Sciences, Faculty of Medicine and Dentistry, University of Bristol, Bristol, UK
| | - H E Lee
- Department of Life and Nanopharmaceutical Sciences, College of Pharmacy, Kyung Hee University, Seoul 130-701, Republic of Korea; Kyung Hee East-West Pharmaceutical Research Institute, College of Pharmacy, Kyung Hee University, Seoul 130-701, Republic of Korea
| | - S J Park
- Department of Life and Nanopharmaceutical Sciences, College of Pharmacy, Kyung Hee University, Seoul 130-701, Republic of Korea; Kyung Hee East-West Pharmaceutical Research Institute, College of Pharmacy, Kyung Hee University, Seoul 130-701, Republic of Korea
| | - Y-K Ryu
- Department of Bioscience and Biotechnology, Sejong University, Seoul 143-747, Republic of Korea
| | - H-C Kim
- Biomedical Mouse Resource Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Taejeon 305-806, Republic of Korea
| | - S Lee
- Faculty of Marine Biomedical Science, Cheju National University, Jeju 690-756, Republic of Korea
| | - J H Ryu
- Department of Life and Nanopharmaceutical Sciences, College of Pharmacy, Kyung Hee University, Seoul 130-701, Republic of Korea; Department of Oriental Pharmaceutical Science, College of Pharmacy, Kyung Hee University, Seoul 130-701, Republic of Korea; Kyung Hee East-West Pharmaceutical Research Institute, College of Pharmacy, Kyung Hee University, Seoul 130-701, Republic of Korea.
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